[Objective] The effects of straw returning combined with reduced chemical fertilizer application on rice yield and nitrogen and phosphorus losses with runoff were studied in order to provide a scientific basis for the recycling and reuse of local agricultural resources and the prevention and control of agricultural non-point source pollution.[Methods] A three-year (2018-2020) field plot experiment was conducted that included two treatments:conventional fertilization (T₁), and straw returning + conventional fertilization reduced by 28.57% for nitrogen and 25.11% for phosphorous (T₂). The concentrations and losses of nitrogen and phosphorus in farmland surface runoff, yield, nitrogen and phosphorus uptake by rice straw and grain, and soil nutrients at harvest were determined.[Results] As the number of straw returning years increased, T₂ achieved a significant increase in yield. Compared with T₁, the yield of T₂ increased by 16.93% in 2020. Compared with T₁, the loss of the total nitrogen and NO^-₃-N for T₂ increased by 6.25%~14.97% and 6.99%~15.03%, respectively. The loss of the soluble total nitrogen, the total phosphorus, and the soluble total phosphorus for T₂ was 0.94%~6.03%, 4.66%~10.32%. and 5.77%~21.15%, respectively, lower than observed for T₁. The interannual changes of total phosphorus, available phosphorus, nitrate nitrogen, and ammonium nitrogen in soil were significant (p<0.05). Compared with T₁, T₂ significantly reduced soil total phosphorus by 8.79% and available phosphorus by 30.56%.[Conclusion] Continuous straw returning combined with reduced chemical fertilizer application ensured the crop yield and reduced the input of chemical fertilizer and the loss of phosphorus in farmland runoff, but increased the risk of nitrogen runoff loss. Therefore, the continuous straw-returning system should be further optimized in actual agricultural production.