Traditional lifetime models of wireless sensor networks don’t take into account the diversity of nodes’ unit transmission cost on different hops.This paper explored this defect and constructed a new lifetime model

then transformed the objective of model into a max-cost max-flow problem with an additional inequality constraint.A heuristic routing protocol

Load Pressure Routing (LPR) algorithm

based on the relation between routing layout and lifetime optimization was presented.LPR needs relatively less computation and communication.LPR is analyzed and validated for performance through simulations

the result of which suggests it can prolong the lifetime of networks efficiently.