Wireless sensor networks（ WSNs） may be influenced by many factors

including interference of wireless links and lack of physical protection

which makes the sensor nodes vulnerable to a variety of attacks launched by malicious nodes and become compromised nodes. In order to address these network security problems

a trust model based on optimized ant colony algorithm is proposed. This model is composed of pheromone update

path quality assessment

trust evaluation and punishment and reward mechanism. In addition

in order to enhance the accuracy of the global pheromone calculation

when global pheromone is calculating

the optimal solution retention strategy is introduced into the trust model. The simulation result show that the trust model has higher performance and reliability and it is more suitable for WSNs.