Active anti-collision system for car

The invention relates to an active anti-collision system for a car, including: a sensing unit, a judgment and decision unit and an execution unit. The car recognizes the ambient environment and the own environment via the sensing unit consisting of sensors, the judgment unit consisting of a single chip machine and software controls and decides the operation of the system by receiving information sent by the sensing unit, the execution unit receives an instruction from the judgment unit, and gives an alarm and executes emergency automatic brake. In the invention, when the distance between the car and a barrier is less than a safety value, an alarm is given out, if the driver has no action, the system brakes automatically to avoid accidents. The invention is suitable for various motor vehicles with an electronic fuel injection control engine.