Abstract: For dense wireless sensor networks (WSN),nodes working staggerly is one efficient approach of extending network's lifetime.An analysis of random sensor scheduling algorithm based on COVER is conducted in this paper.The definition of coverage intensity in k-coverage network is presented and its corresponding formula is estimated using elementary probability theory.A precise analysis about 2-coverage network and a mathematical relationship among coverage intensity,node density and the level of energy conserving (i.e.,the number of deploying nodes n,the coverage intensity of 2-coverage network Cn2,and the number of divided Cover c) are proposed.The result can be applied to deploy an energy-efficiency WSN possessing of high fault-tolerant performance.