In order to solve the problems of high economic costs, large amount of carbon emissions and insufficient attention to social benefits in the closed-loop logistics network for fresh foods, a multi-objective closed-loop logistics network model for fresh foods under uncertain conditions was established by considering the uncertainty of return quantity and aiming at the minimum economic costs, the minimum carbon emissions and the maximum social benefits. Firstly, the improved Genetic Algorithm (GA) was used to solve the model. Then, the feasibility of the model was verified by combining the operation and management data of a fresh food enterprise in Shanghai. Finally, the results of improved GA was compared to the results of Particle Swarm Optimization (PSO) algorithm to verify the effectiveness of the algorithm， and to highlight the superiority of the improved GA in solving multi-objective complex constraint problems. The example results show that the satisfaction degree of multi-objective optimization is 0.92, which is higher than that of single-objective optimization, demonstrating the effectiveness of the proposed model.