综合商社形成的基础是对外投资 ,综合商社的投资决定是综合商社微观研究的基础。本文通过对综合商社投资的内、外因素分析 ,导出了综合商社投资决定函数式。在函数式中说明各因素之间的互补关系 ,并对这种互补关系进行了辩证论述。对资金的缺口提出当国家可供投资资金不足时 ,由商社自有资金补充 ;如果商社自有资金不足 ,可由国内或国际金融市场的借贷资金来弥补。对于国家国际收支的平衡 ,用因素关系式提出了调整补充的方案措施 ,并用埃奇沃斯矩形图描述了商社投资最大效率轨迹线。在上述讨论的基础上 ,对综合商社投资的地区选择、行业选择和部门选择提出了建设性意见 The formation of an integrated trading company is based on foreign investment. The investment decision of an integrated trading company is the basis of the micro-study of a comprehensive trading company. Through the analysis of the internal and external factors of the investment of the integrated trading company, this paper derives the functional formula of the investment decision of the integrated trading company. Explain the complementary relationship between the various factors in the functional formula, and give a dialectic discussion of this complementary relationship. The lack of funds raised by the state when the lack of funds available for investment by the trading company’s own funds to replenish; if the company’s own lack of funds, domestic or international financial markets by borrowing funds to make up. As for the balance of the country’s balance of payments, we put forward the adjustment and supplementation measures and measures by using the relation of factors, and use the histogram of Edgeworthy to describe the maximum efficiency trajectory of business investment. On the basis of the above discussion, we put forward constructive suggestions on the regional selection, industry selection and departmental selection of integrated trading company investment