Based on the heuristic method used to solve set k cover problem, a scheme namely reliable coverage scheme is proposed to solve reliable coverage problem within the cluster in a hierarchical structured network. A minimum cover is a smallest set of sensor nodes capable of complete monitoring over the entire cluster area. 1-resistant minimum cover topology, applied in reliable coverage scheme, is the combination of two minimum covers. Round robin working of 1-resistant minimum covers prolongs network lifetime significantly. The redundant minimum cover shields nodes’ failures from a single minimum cover. In reliable coverage scheme, interaction protocol between cluster head and cluster members is introduced and instant cover replacement algorithm is applied to handle possible members’ failures. Simulations show that this scheme is able to efficiently utilize energy to prolong network lifetime while at the same time keeping missed monitoring at a low level.