Abstract—The implementation methods of the tasks assignment and tasks scheduling for Wireless Sensor and Actuator Network (WSAN) are proposed in this paper. Firstly, the distributed auction algorithm was used to assign tasks to the optimal actuators. Secondly, the Ant Colony Optimization (ACO) algorithm whose parameters were optimized by Particle Swarm Optimization algorithm (PSO) was proposed for the tasks scheduling of each actuator. The optimization features of PSO were used to find the most important parameters of ACO and the performance of ACO was improved. The simulation results show that compared with the other methods of scheduling, the ACO optimized by PSO algorithm (PSO-ACO) has a better performance on moving distance, completion time and energy consumption.