To investigate the effect of reduced fertilization on rice yield and soil fertility, the rice yield, soil organic matter, available NPK and effective copper, zinc, iron and manganese content after 10 years of reduced fertilization and straw returning in the Chaohu Lake Basin were tested. Soil enzyme activity was measured and analyzed. The results showed that long-term nitrogen reduction of 30% or 50% phosphorus reduction had no significant effect on rice yield, but reduction + straw yield had an effect on yield increase, but the yield was not significant; reducing nitrogen by 30% or reducing phosphorus by 50% would reduce soil The content of organic matter increased the content of available potassium and alkali-hydrolyzed nitrogen in the soil. The content of available phosphorus in soil reduced significantly by 50% of phosphorus reduction, and the amount of available organic matter, available potassium, alkali-hydrolyzed nitrogen, and effective copper and zinc were increased by reducing the amount of straw + returned to soil. The iron and manganese content had no significant effect on the increase of available phosphorus. Compared with no fertilizer application, fertilization could significantly increase soil enzyme activity. Decreasing N and P fertilizers would reduce enzyme activity in the soil to a certain extent. The reduction + straw returning to urease The effect of the increase was not obvious, but it would significantly increase the activity of neutral phosphatase and sucrase in soil. There was a significant or highly significant positive correlation between soil enzyme activity and rice yield and soil nutrient content. Considering the effect of reduced fertilization on rice yield and soil fertility, we can put forward the implementation of reducing fertilization and straw returning in Chaohu Lake Basin instead of optimizing fertilization.