The invention relates to a robot sensor network energy supplement method at an express sorting background and belongs to the field of energy supplement of network node of a rechargeable robot sensor network. According to the movement information of the robot sensor, the time and the position where a mobile charging device meets each robot sensor for providing a charging request are calculated; onthe premise that the response fairness problem of the charging request obtained by the robot sensors is considered, the mobile charging device is used for preferentially selecting the robot sensor with the short meeting time to carry out energy supplement with the robot sensor at the meeting position. According to the charging candidate robot sensor selection method, the charging delay can be shortened, and the charging efficiency can be improved. The invention provides a novel method for energy supplement of the robot sensor network at the express sorting background, so that continuous operation of the network can be realized.