Barrier coverage is a research hot topic in wireless sensor networks(WSNs). Due to the high cost of mobile sensors and the high energy consumption during the moving process, it is critial to address the problem with an energy-efficient method to mend barrier gaps. Therefore, we design a weighted graph of stationary sensors, use the Dijkstra algorithm to search the minimum number of mobile sensors required, and construct the shortest path of stationary sensors. According to the requried number of mobile sensors, barrier gaps are divied into simple case and general case. Finally, the Kuhn-Munkres(KM) algorithm is used to solve the minimum movement of the mobile sensors problem. Simulation results show that the proposed algorithm can effectively improve barrier coverage and minimize the moving distance of mobile sensors.