Aiming at the problem of uneven distribution of the optimal solution and local optimality when the multi-objective particle swarm optimization algorithm is used to solve the problem of optimal load distribution, the elite crossover operator is introduced and the non-inferior solution sets are ranked based on the congestion. This paper presents a method to deal with the equality and inequality constraints of the unit output when the network loss is taken into account accurately. Load optimization distribution is performed for the three-unit system with or without network loss. Simulation results show that the improved particle swarm optimization algorithm has improved the optimization ability. When the fuzzy membership function is used to screen Pareto solution set, the result of the method proposed in this paper is obviously better than that of the conventional particle swarm optimization algorithm, which can reduce the cost of power generation and pollutant emission while making the solution strictly meet the constraints.