Considering complex environment of disaster site, an Arm-swing Wheeled Robot (AWR) with auxiliary obstacle-surmounting mechanism was developed. The obstacle-surmounting process is simplified into three stages, and the mathematic model of kinematic for each stage has been established. The simulation for each stage of obstacle-surmounting has been carried out in MATLAB. The stability of obstacle-surmounting is analyzed and the trend of resistance moment is obtained. Finally, the effectiveness of simulation analysis is verified by comparing with the test results of physical prototype.