Wireless sensor networks (WSNs) are widely used in various measurement fields. However, their nodes are characteristic of constrained energy supply, limited hardware resource, large number of nodes, self-organization and dynamic topology, which make networks prone to malfunction. As a result, high reliability and low fault are the basic requirements of WSNs. To prevent too many active nodes and wasting more energy in redundant routing method for WSNs, a fault-prevention technique of controlling redundant routes into sleeping based on health degree is proposed. This technique uses sink node to collect the residual energy of each node, and to calculate energy consumption degree parameter and health degree parameter, and adopts a-star algorithm to control the redundant routes into sleeping mode. The simulation results of NS2 and actual node experimental results show that the present health degree based technique can balance the networks energy consumption and prolong the network lifetime significantly.