To extract an object quickly and exactly is the key technology of a vision system.The substance of object extraction for a vision system is image segmentation.The algorithm to extract object based on the approach of color space reference list is presented.Through image processing,the mass center of the object is calculated and the location of the object is obtained.At the same time,the relationship between the image and CCD space is built by NN.Then the location of the object is acquired.The NN simulation result shows the method is effective and recommendable.