In recent years, with the increasing number of vehicles, traffic congestion has become more serious, resulting in the reduction of timeliness of fresh products in the cold chain logistics distribution process. In order to improve customer satisfaction, ensure the freshness of goods and reduce distribution costs, a cold chain logistics distribution model of fresh products considering traffic congestion was proposed, and the Harris hawks optimization algorithm was improved to improve the solution accuracy. Firstly, based on the traditional cold chain logistics model of fresh products, a new distribution model was constructed by considering various distribution costs while considering traffic congestion. Secondly, in view of the shortcomings of the Harris hawks optimization algorithm, which has slow convergence speed and is easy to fall into local optimality, an improved Harris hawks algorithm was designed to enhance the local optimization ability and improve the solution accuracy. Finally, the performance of the constructed model and the improved algorithm was verified through simulation experiments. Through simulation experiments and comparative analysis, it is proved that the proposed algorithm can obtain the minimum objective function value and the optimal distribution route. The mathematical model and improved algorithm proposed here are effective.