To effectively solve the problem of fast and accurate detection of moving targets in complex surveillance scene, target detection method based on multi-frame background subtraction and Cauchy model is proposed. Firstly, Surendra background model is improved to get clean background image. Then, system judges the current pixel on the absolute differential image belonging to the target areas or background areas by the absolute difference between the current background frame and the real-time video frame. Finally, through the Cauchy distribution model of the pixel, the aim of the moving target detection is realized in complex surveillance scene. The experiment on the vehicle, pedestrian and other object shows that the method can not only suppress the noise and interference of false target, but also can segment foreground target rapidly and accurately.