In order to alleviate the problem of the imbalance energy consumption and hotspot due to the uneven distribution of nodes and the different amount of perception data in the Wireless Sensor Network (WSN), a Path Planning Algorithm of Mobile Sink named MSPPA was proposed to optimize network lifetime and shortest path in WSN. Firstly, by defining the grids in the network area, several candidate sites of mobile sink were distributed in each grid, and then sink node selected a site for sojourning and collecting data of nodes in each grid. Secondly, based on the relationship between network lifetime and the selection of sink sites, an optimization model was established to weigh network lifetime and mobile journey of sink. Finally, the double-stranded genetic algorithm was proposed to plan the order of mobile sink traversing grids and selecting site of the mobile sink in each grid, then the optimal path of mobile sink was obtained. The simulation results show that, compared with Low-Energy Adaptive Clustering Hierarchy (LEACH) algorithm and optimizing LEACH clustering algorithm with Mobile Sink and Rendezvous Nodes (MS-LEACH-RN), the network lifetime of MSPPA was increased by 60%. The proposed MSPPA has a good balance of energy consumption as well. The experimental results indicate that the proposed MSPPA can effectively alleviate the imbalance of energy consumption and the hotspot problems, prolonging the network lifetime.