Abstract: The epidemic outbreak of“COVID 19” seriously endangers people’s life security, while logistics security plays an important supporting role in epidemic prevention and control, protecting people’s lives and stabilizing society.Based on the background of retail logistics distribution to ensure people's livelihood, the vehicle routing problem considering order release dates is studied, and a linear programming model with the goal of minimizing the weighted sum of delivery completion time and transportation costis constructedand an improved iterative local search solution algorithm is designed.In this algorithm, the local search process based on a variety of neighborhood structures and the improved US algorithm is adopted to enhance the optimization ability of the algorithm, and the large path and the optimal split procedure to obtain high-quality initial solution and the breaking mechanism to enhance the search efficiency of the algorithm are introduced.At the same time, some properties for Lagrange relaxation algorithm are proposed to provide a high quality lower bound for the problem in this paper.Finally, the effectiveness of the model and algorithm by solving the benchmark and the numerical instances are verified in the paper, and sensitivity analysis on the order release dates and model parameters are carried out. The results show that the model and algorithm in this paper can provide effective decision support for the efficiency improvement and cost control of retail logistics distribution.In this research, not only a theoretical basis for enterprises to make efficient decision plans in different periods of operation requirements is provided, but also some enlightening significance to the similar problems with the requirement of time and transportation cost balance in practice is provided.

Key words: epidemic outbreak; retail logistics; order release dates; routing optimization