Abstract: In this paper, what three kinds of paths effect on manipulator between two configurations for mobile platform is studied. We point out that the configuration which needs reversal path should be avoided when we plan mobile manipulator's two configurations; the best configuration of mobile platform for manipulator should be in regions where the configuration can be transferred by direct path,when mobile manipulator's coordination is discussed, this point shouldn't be neglected, and is the basis for optimal criterion of mobile manipulator.