In order to solve the problems of low coverage balance performance, low quality of life of nodes and serious fluctuation of network transmission performance in the process of wireless sensor network deployment, a WSN balanced coverage algorithm based on weight threshold liberalization mechanism is proposed. Firstly, the infection mechanism is introduced and the network nodes are regarded as infection particles. A weight optimization method based on redundant coverage strategy is designed. The redundant coverage coefficient is calculated according to the weight coefficient of each particle, and the nodes with increased redundant coverage coefficient are shifted to improve the evaluation ability of the network on the degree of redundant coverage. Then, combined with the initial coordinates, maximum coverage radius, redundant coverage weight and other coefficients of the node to build a decision model, a node mobile coverage method based on threshold decision mechanism is designed. The node variance is verified by the time-lapse coordinates, and the decision threshold is further constructed by the node variance. The nodes whose decision threshold is not higher than 1 will not be moved, which reduces the loss due to movement Network coverage is reduced due to network failure. Simulation results show that: compared with WSN coverage optimization algorithm based on global local search mechanism and WSN robot coverage algorithm based on improved filtering mechanism, The proposed algorithm has higher node survival rate and network transmission bandwidth, which reach 90% and 3780mbps respectively in Gaussian channel.