With the increasing requirements of video monitoring system’s intelligence

tracking moving object has been a hotspot. It is a problem needs be to addressed that how to detect object’s depth moving state（the size of object) only with 2D video signal and control the camera’s zoom. This paper proposes a method of tracking moving object in 3D-space based on genetic searching algorithm. The object’s 3D contour feature can be searched and matched using genetic algorithm to detect the location and the size of a moving object. Then

the camera’s zoom can be controlled. This method can ensure a relatively stable size of the moving object in the video screen and improve the quality of the monitoring system.