中文摘要：

为研究考虑产品替代的竞争供应链物流外包决策,在双寡头竞争环境下,构建以两家制造商为主导的两条相互竞争的供应链模型,应用博弈论研究第三方物流（3PL）服务商的低成本效应和双重边际效应对供应链物流外包决策的影响,并给出最优物流策略建议。研究表明：3PL服务商的低成本效应和双重边际效应平衡的结果决定是否引入3PL服务商;产品替代性对供应链物流外包决策有重要影响;产品替代性越高,3PL服务商的低成本效应和双重边际效应对供应链的影响越小。通过数值算例对结论进行验证。

英文摘要：

In order to study logistics outsourcing decisions of competing supply chains considering product substitution,the model of two competing supply chains is developed,where two supply chains are dominated by two manufacturers respectively in the duopoly competition environment. The low cost effect and double marginal effect of 3rd-Party Logistics（ 3PL） providers on logistics outsourcing decisions are studied by the game theory,and the optimal logistics strategy is given. Results show that： the balanced result between the low cost effect and the double marginal effect decides whether or not introducing 3PL providers; the logistics outsourcing decision is greatly influenced by product substitution; the higher the product substitution,the smaller the low cost effect and the double marginal effect of 3PL providers. The conclusions are verified through numerical examples.