Wireless　sensor　networks　have　profound　effects　on　many　application　fields,　whereas　applications　in　mobility　scenarios　need　an　immediate,　fast,　secure　and　energy-efficient　route.　In　this　paper,　we　build　a　secure　tree-structure　route　for　mobility　scenarios　in　the　large-sized　wireless　sensor　networks　with　only　a　resource-constrained　sink　node.　After　mobile　nodes　securely　rejoining　the　network,　we　can　adapt　the　network　topology　changes　by　moving　the　sink　node　and　reconstructing　the　route.　Analysis　shows　that　our　routing　scheme　is　energy-efficiency　in　terms　of　computation,　communication　and　storage.