SUMMARY
In order to improve the security of wireless sensor network, the trust model of wireless sensor network based on cloud theory is established. The similarity comparison algorithm is introduced. Trust is expressed as a quantitative value. The new update function is designed to make the acquisition of trust more reasonable. In the research method and algorithm design, the wireless sensor network is different from the traditional network security. The balance problem of wireless sensor network security in algorithm computing strength and security intensity is studied. The results show that the trust model has good robustness. It can identify the malicious nodes accurately and quickly, and prevent the network from being destroyed. Therefore, the idea of cloud theory can effectively improve the security of the network.