Abstract: The dynamic avoiding collision with moving obstacles of mobile robot is studied. For the existing problems of the previous velocity obstacle methods used for dynamic collision-avoidance,corresponding improvement methods are worked out. The velocity changes of obstacles,collision distance and collision time are considered synthetically. In the velocity change space,a new evaluation function based on collision-avoidance behavior dynamics is designed for the dynamic collision-avoidance planning using two obstacle finding windows. Simulation experiments show that the proposed methods effectively overcome conservativeness of collision-avoidance planning,improve motion security of robot,and can be implemented to pursue the moving goal in time.