When my car is on the wiper will start working without stopping until you put the car off, what is the cause and how can I solve it.

Bad wiper control, short circuit? Has the car been in any collisions recently? Any flooding in your area? Any recent repairs performed?
Can you tell us make and model year etc? How long have you owned the car?

Check/replace the combination switch. First, try disassembling and cleaning the switch.