Hi.
I am in CA.
I have recently been offered a job.
The new employer has requested me for a paystub about my previous jobs?
Isn't this kindof personal information?
Or its okay for them to demand this information?

Also, at least one employer (staffing firm who subcontracted my services) I recently worked with had me sign a contract saying all Pay Information is confidential between them and me.
Can I still forward a paystub to the new employer?

Thanks for your advice.

Yes, a prospective employer is allowed to ask for that information.

Whether or not you are prohibited by doing so by the agreement you reference, will depend on the EXACT wording of the agreement. You will need to show it to a local attorney.