The developing countries have changed the aim of absorbing FDI in the few decades as they enhanced the opening level and accelerated the opening speed.They think that FDI is the chanel to acquire the advanced management and technology,not just international capital.The technology spillover effect(TSE) of FDI has aroused increasing attention from the various countries.The time lag was neglect in the current positive research on TSE of FDI.The TSE's time lag has been estimatied with the method of Granger Causality Test in this paper.The caculated result has been explained to provide the scholars and policy decision-makers' some advice for promoting adjustment and deepening of our country's reform strategy.