To investigate the effect of polyaspartic-urea onrice，especially the effect of reducing N concentration in surfacewater and controlling N non-point source pollution ofrice，a field experiment was carried out to explore how polyaspartic -urea affects the changes of N concentration in paddy field surface water，the yield and N uptake ofrice.Samples of paddyfield surface water were collected continuously after each fertilizer application for analysis of total N(TN)，NH 4+-N and NO^3--N.The results showed that the grain yield of polyaspartic -urea was slightly higher than that of common urea by2.9%，and it had no significant effect on the effective panicle number，but could increase the number of grains per panicle and1 000 grain weight to a certaindegree.Inaddition，N uptake of polyaspartic -urea was slightly higher than that of commonurea by10.5%.The average concentrations ofTN，NH 4+-N，and NO 3--N in the surface water of polyaspartic-urea were 10.6%，11.1% and 5.4% lower than that of common urea treatment in the early stage(1～7 days after basalfertilizer，1～ 5days after tillering fertilizer and 1～ 3 days after earfertilizer).However，the dynamic change rules ofTN，NH 4+-N，and NO^3--N concentrations in the surface water of polyaspartic-urea were consistent with that of commonurea，and there was no difference in NH4+-N/TN，NO 3--N/TN of surface water between the two treatments.So polyaspartic -urea can increase riceyield and promote the absorption ofnitrogen，and reduce the concentration of nitrogen in the surface water of ricefield.It is a new type of fertilizer that can be used to prevent and control the loss of nitrogen in rice field and ensure rice yield.