A practical tracking system should be equipped with scale adaptation mechanism.To solve the problem of the traditional methods which could not keep up with the scale changing timely and accuratelythe particle filter and an improved Mean Shift method were introduced to locate the centroid of the target.Thenthe correlation coefficient was adopted to map the object and its candidate in the LogPolar Transformation domain to fit the target scale.Experimental results demonstrated that the composite algorithm can select a proper size of tracking window adaptively.Compared with the traditional methodit has a better robustness.