【摘要】Foreign direct investment (FDI) is deemed to an engine of economic development,but overusing FDI may lead to side effect. Evaluating the crowd\|in or crowd\|out effect of FDI on domestic Investment is an important aspect of evaluating FDI effect. Does FDI crowd out China's domestic Investment?The author's answer is positive.The paper puts forward an investment model and an evaluating coefficient (the observation period:1983～1999) and finds out FDI have crowded out China's domestic Investment.Thus it is necessary to adjust the policy of utilizing foreign capital.