Combing the future developing direction of network, we advance a new tiered mobile sensor network. Based on this new network, movement control policy of data collecting node-sink, and problems of instability of network and high-fraction of event loss caused by the tiered mobility of S(sensor node) and sink node are researched. We propose adopting mobile sink nodes to produce limitary Voronoi partition, respectively controlling each sink node's movement control policy. Then combine area partition with collect-blind calculating algorithm to design each sink node's optimal mobile route. From the simulation, it obviously indicate that it can obtain higher network coverage rate and lower event loss rate, only need a small quantity of sink nodes. The proposed movement control policy of sink nodes provides a good solution to the problems of instable communication and high-fraction of event loss on tiered mobile sensor network.