In order to solve the problem of the dynamic obstacle avoidance of the mobile robot in indoor environment, a new approach based on depth information is presented in this paper. The depth information of surrounding environment was collected and used to set the robots obstacle avoidance warning area by a Kinect sensor. When the moving obstacle accessed into the warning area, the robots obstacle avoidance direction was determined preliminary by the obstacles position, and then an improved Kalman filter algorithm was used to optimize the avoidance path. Experiments show that this approach can overcome the potential problem of path selection, and realize the mobile robot obstacle avoidance behavior in the dynamic environment.