Braking performance test methods are compared and analyzed. ABS will not work if the speed is too low when the automobile is tested by tester and load testing. Since the braking performance can not be evaluated accurately in this case, the theoretical calculation of braking distance is given in this paper. The calculation result shown the potential of braking performance is mainly on high speed for the automobile with ABS. High-speed road test is designed, and the test results are close to calculation ones, so calculation model is of accuracy. It is less error and better precision than existing calculation way, this method is effective and accurate.