The Shuibuya Reservoir on Qingjiang River was selected to illustrate the source and sink of greenhouse gas from the cascade hydroelectric power stations. In-situ measurements were carried out in May and October, 2010 to obtain carbon dioxide and methane exchange fluxes from water-atmosphere interface of the reservoir, the vertical profile of greenhouse gas concentration above water-body and the aquatic environmental factors respectively. It is revealed that the highest carbon dioxide concentration measured in May, 2010 was below 0.5 meter in the vertical profile, and the water surface temperature has the largest effect on the concentration change and fluxes of carbon dioxide from the reservoir 's water-body. Overall, carbon dioxide and methane was emitting from the water-atmosphere interface of Shuibuya Reservoir's water-body in October, 2010, with the mean fluxes amounting 3 740.92 ±1 872.56 mg.m-2d -1 and 1.22±0.57mg.m-2d -1 respectively, close to those from Taihu Lake and East Lake and other natural water bodies in China, much lower than those from the reservoirs in the tropic or temperate zones. The carbon dioxide fluxes increased from the upstream to the dam ； while methane fluxes presented to be the opposite. This study provided in-situ measured data for understanding the sink and source of greenhouse gas emission from reservoirs and scientific support for the development of hydroelectric clean energy of the upstream Yangtze River.