Abstract: The number of boundary nodes neighbors is less than that of the internal nodes in highdensity deployment wireless sensor network， which will lead to unequal probability of sleep and the problem of boundary contraction. To solve the problems， a nodes lightweight scheduling algorithm was proposed to prevent boundary contraction. The number of nodes in neighbor table and the number of neighbor nodes’ working neighbors were used to determine whether the node was in the network boundary. For those boundary and internal nodes， different scheduling strategies were used. The probability of nodes covered completely by n neighbors in the network boundary and the range of area fraction of the boundary node covered by n neighbors were calculated， respectively. The simulation results showed that the boundary contraction can be effectively alleviated and the network life cycle can be extended by using the proposed algorithm.

Key words: wireless sensor networks(WSN), nodes sleep, preventing boundary contraction, boundary nodes determine, energy