i have project that modify 1000 jcl ,and some string will be changed,but need to keep the member's statistics.
a good idea. If you are altering the member, you want to update its last modification date in the directory.
I'm confused here. If you do not want to alter the directory, why on earth are you asking a question about how to alter the directory?
Other than ISPF services and programs like the Binder, few programs create user data in directory entries. While it's not difficult, I don't think I've ever seen a formal statement about the contents of the user data in an ISPF directory entry.
"...modify 1000 jcl ..." is improper terminology. You want to say "... modify 1000 JCL members ..."