设施位置与设施容量是影响供应链长期运营成本和服务质量的重要因素，也是企业获得竞争优势的两个决定性因素。针对设施选址及容量选择优化问题，本文提出以最小化成本为目标的混合整数规划模型，对工厂和仓库的位置及容量，工厂到仓库的产品流和客户到仓库的分配进行优化。根据模型特点设计拉格朗日松弛算法对其进行求解，为了提高解的质量，本文开发混合模拟退火禁忌搜索算法对拉格朗日松弛算法的求解结果进行改进。本文利用随机生成的大量具有不同规模及参数的实例对算法的有效性进行检验，数值实验表明该算法适用于同时优化设施选址及容量选择问题。

The facility location and size are important factors that affect operation cost and service quality of supply chain, and also two decisive factors for enterprises to gain competitive advantage. In order to optimize facility location and size simultaneously, a mixed integer programming model is formulated to minimize the total costs, and to decide the location of plants and depots, select sizes for the plants, determine the product flows from the plants to the depots and assign the customers to the depots. According to characteristics of the problem model, a Lagrangian relaxation algorithm is designed to solve the problem, and a hybrid simulated annealing tabu search algorithm is developed to further improve the solution quality. To test the validity of the proposed algorithm, a large number of randomly generated instances of different sizes and parameters are provided. The numerical results indicate that the proposed algorithm is effective and efficient for the two-echelon facility location problem with choice of facility size.