In order to solve the problems of trust deciding and its dynamics evolving which will be faced during the process
of creating trust relations between sensor nodes in wireless sensor networks(WSNs), an incentive mechanism bound by
trust level is introduced, and the model of WSNs trust game is created for reflecting the limited nationality and utilities of
each game stage. Based on evolutionary game theory, the evolutionary process of selecting trust strategy of sensor nodes is
researched. The replicator dynamics of trust evolving in WSNs is given. The theorems in which evolutionary stable strategy
under different parameter values can be satisfied are proposed and proved, which can provide theoretical foundations for
designing a WSNs trust mechanism. The experiments show the conclusions attained from proposed theorems and the effect
of the incentive mechanism.