A major problem today for car owners is that they are in constant fear of having their vehicles stolen from a common parking lot or from outside their home. Image processing based real time vehicle theft detection and prevention system provides an ultimate solution for this problem. In this project, a low-cost extendable framework for smart car security system is proposed, which consists of a FDS (Face Detection Subsystem), a GPS (Global Positioning System) module, a GSM (Global System for Mobile Communications) module and a control platform. The system described in this project automatically take photos of driver and compares his or her face with database to check whether he is an authenticated driver or not. The face detection subsystem bases on optimized PCA (Principle Component Analysis) algorithm and can detect faces in cars. The other modules transmit necessary information to users and help to keep eyes on cars all the time, even when the car is lost. This system prototype is built on Android Board, controls all the processes. The owner is made able to perform car stopping through the message from his mobile. The GPS module in the car detects the location of the car. So by this system, the identifcation of the thief and the location of the car are simply smarter and cheaper than traditional one.