Because of the limited energy of wireless sensor network, the optimization of network lifetime becomes a primary problem in the design of the network. Through analyzing the node residual energy and the load effect on the node lifetime, the fault tolerant topology evolution model in wireless sensor networks is put forward for extending lifetime. And the scope of load adjustment coefficient is obtained under the condition of network survival time. The simulation results show that the topological structure based on the evolution of the scale free network has the good fault tolerance characteristics. And it can also balance the network node energy consumption and the lifetime extension of the network.