The Yellow River irrigation area within Ningxia was a region severely polluted by non-point sources, where surface water quality in most drainage ditches was classified as Inferior Category V, and the primary pollutants were nitrate and ammonium. In this region a 5-year straw application and nitrate leaching experiment had been conducted, which consisted of 3 treatments: traditional fertilizing without rice straw amendment(CK), traditional fertilizing with 4500 kg/hm² rice straw returning application (T1, semi), and traditional fertilizing with 9000 kg/hm² rice straw amendment (T2, total). Nitrate nitrogen leaching losses within 10, 20, 30, 60, 90 cm soil layers were measured by the resin core method. Results indicated straw application could reduce soil nitrate leaching losses within the 30 cm layer. From the nitrate nitrogen loss of CK (15.76 kg/hm²), the loss of T1 (13.76 kg/hm²) and T2 (13.74 kg/hm²) all showed significant differences (P < 0.05), soil nitrate leaching losses were decreased by 12.71% and 12.84%, respectively. However no significant differences (P > 0.05) was detected between T1 and T2. The effects of straw application were only observed in plowing layer (30 cm depth soil layer), no significant difference was detected between experimental treatments and control (CK) in deeper layers (60 and 90 cm) and in topsoil (10 and 20 cm). Straw application could increase soil organic matter (SOM) and total nitrogen (TN) content: SOM of T1 and T2 were increased by 0.89 g/kg and 1.24 g/kg compared to CK (13.78 g/kg). TN of CK, T1 and T2 were 0.64, 0.66 and 0.69 respectively, at 0-30 cm layer, which were increased by 2.76% and 6.83%. Straw application could also increase crop yield,rice production of T1 and T2 were increased by 9.24% and 10.37%, and winter wheat yield were increased by 10.11% and 11.51%, respectively.