A practical tracking system is required to update the appearance changes of moving objects in real-time.The system with fixed-size tracking window could not trace an object effectively when scale of the object has distinct changes

therefore it is important to select the scale of tracking window automatically.The information measure of multi-scale image in scale space has been used to differentiate the scale and is introduced into moving object tracking in this paper.Automatic updating method of tracking window is proposed

and is integrated into the classical Mean-Shift tracking algorithm based on color histogram.Experimental results demonstrat that the improved algorithm could select the proper size of the tracking window in the scenarios that not only of increasing scale but of decreasing scale.