my win8 RP can not creat Pin password or picture password. Does anyone know the reason???

I could not in Win 8 CP, but when I clean installed Win 8 RP the picture PW is working fine. Others had this feature in Win 8 CP. I suspect there is something wrong in your installation. My CP installation most likely had a problem as well, but since we were so close to Win 8 RP, I just waited.

In your case, it might be worth trying a Reset. Be advised however that a Reset will wipe out any W32 apps you have added. It will make a list for you of the apps it kicked out, but they will have to be reinstalled. A Reset does save the Metro apps and customizations. I would suggest if you would like to try this, back up all you data (Pictures, Music, My Documents, Favorites, Contacts, any app data, etc) If you create a back up of this data it can be restored after you have performed the Reset and reinstalled the apps the Reset lost.