Macroeconomic conditions for large-scale investment abroad of a power are discussed in two angles of logic and history. Under the supply-constrained economic situation，since the capital stock is in shortage and the domestic investment space is wide，so not only the investment abroad isn’t required in the macro economy of one country but also the ability of investment abroad is very low，and even the FDI is welcomed into home country. At the beginning of demand-constrained economy，the domestic investment depends on the consumptions and exports. As long as the government promotes the consumption demand by adapting the macroeconomic adjustment policies or the export demand rises，the domestic investment still has larger space but the investment abroad isn’t very urgent. At the mature stage of demand-constrained economy，the potential demands are fairly close to the effective demands and the domestic private investment space is quite narrow，and hence it’s urgent need of the macro economy to invest in the suitable foreign regions. Meanwhile，the investment abroad can also pull the capital goods output of home country which not only lets the GNP increase but also can promote the GDP increase.