How to use the dbms_sql to get the analyze for insert into statement declare 
 v_cursor number;
 stmt varchar2(2000);
 s varchar2(40);
 cursor cc1 is select voc.SQL_ID from v$open_cursor voc left join v$sql vs on voc.SQL_ID=vs.SQL_ID  where voc.SID in(select sid from v$mystat) and to_char(substr(vs.SQL_FULLTEXT,1,2000)=stmt;
begin
delete from table1;
v_cursor:=dbms_sql.open_cursor;
stmt:='inset into table2 (column1,column2) values(''a'',''b'')';
dbms_sql.parse(v_cursor,stmt,dbms_sql.native);
insert into table1 select * from tables(dbms_xplan.display
open cc1;
loop
fetch cc1 into s;
exit;
end loop;
close cc1;
insert into table1 select * from(dbms_xplan.display_cursor(s,0,'ALL'));


I execute this and select  from the table1 but the record in table1 is tells me:


  it could also be that the plan is no longer in cursor cache(check v$sql_plan).


But if I change the stmt to update statement and execute, the record in table1 is correct.
So i want to know where can I get the analyze about the insert statement.
The child_number argument to dbms_xplan.display_cursor needs to be taken from v$sql as well, it's not necessarily zero. (I'm not exactly sure what influences that number, but dropping and recreating table2 in your example gives me a new child_number each time).

Here's a modified version of your procedure (fixed a few typoes in what you have above):

DECLARE
  v_cursor NUMBER;
  stmt     VARCHAR2(2000);
  s        VARCHAR2(40);
  cn       NUMBER;
  CURSOR cc1
  IS
    SELECT voc.SQL_ID, vs.child_number
    FROM v$open_cursor voc
    LEFT JOIN v$sql vs
    ON voc.SQL_ID  =vs.SQL_ID
    WHERE voc.SID IN (SELECT sid FROM v$mystat)
      AND TO_CHAR(SUBSTR(vs.SQL_FULLTEXT,1,2000))=stmt;
BEGIN
  DELETE FROM table1;
  v_cursor:=dbms_sql.open_cursor;
  stmt    :='insert into table2 values (''a'',''b'')';
  dbms_sql.parse(v_cursor,stmt,dbms_sql.native);
  OPEN cc1;
  LOOP
    FETCH cc1 INTO s, cn;
    EXIT;
  END LOOP;
  CLOSE cc1;
  -- To inspect the child number:
  -- dbms_output.put_line(s || ' '|| cn); 
  INSERT INTO table1 SELECT * FROM table(dbms_xplan.display_cursor(s,cn,'ALL'));
END;
/