Field experiment was conducted in black soil region of Northeast China to reveal the effects of straw mulching on runoff,sediment and nitrogen and phosphorus loss in different slope experimental plots at different growth periods of corn. The results showed that,surface runoff,soil,nitrogen and phosphorus losses were increased with the increased slope. Under the condition of corn planting,rainfall was positively correlated with surface runoff,but not for soil loss. The reduction rate of straw mulching on soil loss increased with the decreasing slopes. The resistance control rate of straw mulching on surface runoff and soil loss both exceed 90%. Dissolved nitrogen was the main contributor in nitrogen loss in soil,which accounted for more than 60% of total nitrogen. The loss of phosphorus was mainly granular phosphorus is the dominant phosphorus form,which accounted for more than 80% of the total phosphorus. Straw mulching had a resistance control rate of more than 85% for total nitrogen and total phosphorus in soil,which was of positive significance for controlling soil erosion and reducing the risk of non-point source pollution.