Based on the core issues of the wireless sensor network security model, this paper proposes a new design of pre-shared key pool, which is applied in the area-based key management scheme to ensure network security. This scheme designs a pre-allocated shared key pool architecture based on time variables of one-way hash function, adds time parameters to key negotiation, node update, etc., updates the key through the time mechanism and detection mechanism, and effectively guarantees both forward and backward security of the node. For the problem that local nodes are easily captured, this paper designs a key update mechanism based on security events, namely a key pool update mechanism based on a one-way hash key chain. This new one is based on a one-way hash key chain. The key pool satisfies the security requirements for key generation and updating. After theoretical analysis and simulation, it is proved that node connectivity, node storage energy consumption, and anti-capture capability in the proposed improvement scheme are better than the original one.