Abstract: A miniature two-wheeled robot system called MSTRbot is proposed for reconnaissance and surveillance missions. MSTRbot carries a folding and two-degree-of-freedom arm,using the "grasp" and "support" actions to assist the robot to climb over obstacle.MSTRbot has a cylindrical shape,55 mm in diameter,240 mm in length.MSTRbot can climb over obstacles larger than its own size.The robot can sense its environment by micro audio/video sensors carried,and report its findings to the control center by wireless way.Through experiments and analysis,the adaptable topography environment of the robot is given,and under that environment,the obstacle negotiation experiments is implemented.Experimental results verify that the designed arm on the MSTRbot improvement the performance and capability of obstacle negotiation,and the miniature robot prototype can complete reconnaissance and surveillance missions in complex environment.