diff --git a/src/main/java/com/alibaba/druid/sql/dialect/oracle/parser/OracleStatementParser.java b/src/main/java/com/alibaba/druid/sql/dialect/oracle/parser/OracleStatementParser.java
index 5378001ebb..ad9a4032d1 100644
--- a/src/main/java/com/alibaba/druid/sql/dialect/oracle/parser/OracleStatementParser.java
+++ b/src/main/java/com/alibaba/druid/sql/dialect/oracle/parser/OracleStatementParser.java
@@ -1661,6 +1661,11 @@ public class OracleStatementParser extends SQLStatementParser {
             SQLAlterTableDropIndex item = new SQLAlterTableDropIndex();
             item.setIndexName(indexName);
             stmt.addItem(item);
+        } else if (lexer.token() == Token.PRIMARY) {
+            lexer.nextToken();
+            accept(Token.KEY);
+            SQLAlterTableDropPrimaryKey item = new SQLAlterTableDropPrimaryKey();
+            stmt.addItem(item);
         } else {
             throw new ParserException("TODO : " + lexer.info());
         }
diff --git a/src/main/java/com/alibaba/druid/sql/parser/SQLStatementParser.java b/src/main/java/com/alibaba/druid/sql/parser/SQLStatementParser.java
index f579aff509..35ac7698f2 100644
--- a/src/main/java/com/alibaba/druid/sql/parser/SQLStatementParser.java
+++ b/src/main/java/com/alibaba/druid/sql/parser/SQLStatementParser.java
@@ -1406,6 +1406,11 @@ public class SQLStatementParser extends SQLParser {
             SQLAlterTableDropIndex item = new SQLAlterTableDropIndex();
             item.setIndexName(indexName);
             stmt.addItem(item);
+        } else if (lexer.token() == Token.PRIMARY) {
+            lexer.nextToken();
+            accept(Token.KEY);
+            SQLAlterTableDropPrimaryKey item = new SQLAlterTableDropPrimaryKey();
+            stmt.addItem(item);
         } else {
             throw new ParserException("TODO " + lexer.info());
         }
diff --git a/src/test/java/com/alibaba/druid/bvt/sql/db2/DB2AlterTableTest_drop_pk.java b/src/test/java/com/alibaba/druid/bvt/sql/db2/DB2AlterTableTest_drop_pk.java
new file mode 100644
index 0000000000..d83076ea60
--- /dev/null
+++ b/src/test/java/com/alibaba/druid/bvt/sql/db2/DB2AlterTableTest_drop_pk.java
@@ -0,0 +1,49 @@
+/*
+ * Copyright 1999-2017 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.alibaba.druid.bvt.sql.db2;
+
+import com.alibaba.druid.sql.SQLUtils;
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.dialect.oracle.parser.OracleStatementParser;
+import com.alibaba.druid.sql.dialect.oracle.visitor.OracleSchemaStatVisitor;
+import com.alibaba.druid.sql.parser.Token;
+import com.alibaba.druid.util.JdbcConstants;
+import junit.framework.TestCase;
+import org.junit.Assert;
+
+public class DB2AlterTableTest_drop_pk extends TestCase {
+
+    public void test_alter_constraint() throws Exception {
+        String sql = "alter table supplier drop primary key;";
+        SQLStatement stmt = SQLUtils.parseStatements(sql, JdbcConstants.DB2).get(0);
+
+        OracleSchemaStatVisitor visitor = new OracleSchemaStatVisitor();
+        stmt.accept(visitor);
+
+        System.out.println("Tables : " + visitor.getTables());
+        System.out.println("fields : " + visitor.getColumns());
+        System.out.println("coditions : " + visitor.getConditions());
+        System.out.println("orderBy : " + visitor.getOrderByColumns());
+
+        String output = SQLUtils.toSQLString(stmt, JdbcConstants.DB2);
+        Assert.assertEquals("ALTER TABLE supplier\n" +
+                "\tDROP PRIMARY KEY;", output);
+
+        Assert.assertEquals(1, visitor.getTables().size());
+        Assert.assertEquals(0, visitor.getColumns().size());
+    }
+
+}
diff --git a/src/test/java/com/alibaba/druid/bvt/sql/oracle/alter/OracleAlterTableTest25_drop_pk.java b/src/test/java/com/alibaba/druid/bvt/sql/oracle/alter/OracleAlterTableTest25_drop_pk.java
new file mode 100644
index 0000000000..147737acc8
--- /dev/null
+++ b/src/test/java/com/alibaba/druid/bvt/sql/oracle/alter/OracleAlterTableTest25_drop_pk.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright 1999-2017 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.alibaba.druid.bvt.sql.oracle.alter;
+
+import com.alibaba.druid.sql.SQLUtils;
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.dialect.oracle.parser.OracleStatementParser;
+import com.alibaba.druid.sql.dialect.oracle.visitor.OracleSchemaStatVisitor;
+import com.alibaba.druid.sql.parser.Token;
+import com.alibaba.druid.util.JdbcConstants;
+import junit.framework.TestCase;
+import org.junit.Assert;
+
+public class OracleAlterTableTest25_drop_pk extends TestCase {
+
+    public void test_alter_constraint() throws Exception {
+        String sql = "alter table supplier drop primary key;";
+        OracleStatementParser parser = new OracleStatementParser(sql);
+        SQLStatement stmt = parser.parseStatementList().get(0);
+        parser.match(Token.EOF);
+
+        OracleSchemaStatVisitor visitor = new OracleSchemaStatVisitor();
+        stmt.accept(visitor);
+
+        System.out.println("Tables : " + visitor.getTables());
+        System.out.println("fields : " + visitor.getColumns());
+        System.out.println("coditions : " + visitor.getConditions());
+        System.out.println("orderBy : " + visitor.getOrderByColumns());
+
+        String output = SQLUtils.toSQLString(stmt, JdbcConstants.ORACLE);
+        Assert.assertEquals("ALTER TABLE supplier\n" +
+                "\tDROP PRIMARY KEY;", output);
+
+        Assert.assertEquals(1, visitor.getTables().size());
+        Assert.assertEquals(0, visitor.getColumns().size());
+    }
+
+}