With the development of car industry and carrying trade, serious traffic accident threatens the safety of people and property. It proves the essentialty and instancy of developing the intelligent active security system. The system based on the DSP, can overcome the flaw of the system based on the radar,microwave and ultrasonic. With the TMS320C6201 DSP and the algorithm of computer vision and mode identity, it can find the rode, roadblock and the distance of roadblock . With small volume,portable,easy install,adaptability with atrocious environment and low price, the system can meet the desire of practicability. A lot of experiment prove that the design of the system is advanced and reasonable, and can be adapted to the intelligent aided drive of all kinds of car. The system has the good value of popularize and employ.