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The temporal and spatial distribution of mercury(Hg)in four different sources of stream(aquaculture wastewater,bare land,forestry land and agro-forestry land)and well water of a livestock and agro-forestry watershed in Three Gorge Reservoir region was studied during the period from March 2013 to March 2014.Total mercury(THg)concentrations ranged from 9.95~15.26 ng ? L-1 with an average of 11.95±1.87 ng ? L-1,bare land>aquaculture wastewater>forestry land>agro-forestry land>well water; Total methylmercury(TMeHg)concentrations ranged from 0.120~0.441 ng?L-1 with an average of 0.232±0.099 ng?L-1,aquaculture wastewater> agro-forestry land > forestry land >bare land >well water.THg and TMeHg in well water were both dominated by dissolved fraction,whereas for other sources of stream particulate phase accounted for a major fraction of THg and TMeHg.THg concentration in winter and spring were significant higher than that of summer and fall,however,no obvious seasonal trend of TMeHg distribution was observed.Comprehensive analysis showed human activities and weather conditions such as air temperature and precipitation etc.were main reasons for the difference of temporal and spatial distribution of THg and TMeHg.Overall,THg and TMeHg concentrations in water of study area were higher than that of unpolluted water bodies,indicating that the water in the study area has been a certain degree of human impact.