An oil valve and password controller for car anti theft (PCCAT) has been developed in this research.The oil valve is equipped near the fire system of car and the PCCAT is installed on the operational platform in the car.With the valve and the PCCAT,everyone who wants to drive the car must correctly input the password to open the valve installed between the oil pump and the fire system of the car to make the oil pipe connecting firstly, and then,to start the car engine. It also designed an alarm module in the PCCAT for car to start the alarm system and lock the keyboard when wrongly inputs password over the limited times.In order to avoid being abnormally powered off of the PCCAT and being cut off mistakenly the oil pipe,the PCCAT memory unit can remember and keep the position of the step motor,which could help drivers to avoid inputting password again to restart the engine quickly after engine flameout. At last,it carried out experiments with a motorcycle engine,and the experimental results proved that the PCCAT had better effects for car anti theft.