In view of moving object detection is satisfactory with traditional methods in complex environment, an object detection method based on channel differencing combined with optical flow was proposed in this paper. Firstly, pre-processing including noise reduction and smoothing was introduced to enhance the useful information. Then the moving object was accurately detected and extracted by real-time channel-difference. Lastly, the proposed method combined with optical flow can detect true target and correct detection error by movement information. To improve the effect of detection, mathematical morphology was incorporated into the proposed method to wipe off noise and strain. The experiments show that this method can detect moving objects in image sequence quickly and accurately.