Abstract: Based on hydrometric and meteorological dada, effect of human activities and precipitation on sediment yield of the Jialingjiang River basin has been evaluated by using empirical statistical approach. The results show that soil-water conservation measures and hydraulic engineering works have resulted in significant reduction of sediment yield in the Jialingjiang River basin since the 1980s. A "base-line" (1956-1982) and a "monitoring" (1983-2000) periods have been identified, and regression equations between annual sediment yield in the Jialingjinag River basin and area-averaged annual precipitation is established, separately. Based on the two equations, the sediment reduction induced by the decrease in precipitation and by soil-water conservation measures and hydraulic engineering works was differentiated. As a result, the sediment reduction by the decrease in annual precipitation in the "monitoring" period, the sediment reduction by soil-water conservation measures and hydraulic engineering works, and their percentages of the total sediment reduction have been estimated. This study indicates that the sediment reduction by soil-water conservation measures and hydraulic engineering works (ΔQ_s) depends on annual precipitation (P), the former decreasing with the latter. When annual precipitation exceeded some threshold, negative ΔQ_s would occur. The ΔQ_sincreased with P, and when P=970 mm, ΔQ_sbecame the maximum,and then ΔQ_sdecreased to 0 when P=1180 mm.