Focusing on the problem that the spawning time of the Chinese sturgeon has been delayed to November due to the impoundment of the Three Gorges Reservoir(TGR), this paper studied one of the key factors, water temperature, that influences the reproduction process. Based on the measured water temperature and meteorological data at typical cross-sections upstream and downstream of the Three Gorges Dam and the Gezhou Dam, water temperature variation during the first decade after the impoundment of TGR(2003-2012)and its effects on water temperature characteristics in the Chinese sturgeon spawning reach located in the downstream of Gezhou Dam were analyzed. The result shows that after the impoundment of TGR, water temperature in the reservoir is higher than before, having substantial effects on the downstream reaches. Local air temperature variation is closely related with the water temperature variation and it can be a fundamental reason for water temperature rise in the spawning reach, accounting for a contributing degree of about 61%.