Based on the results of a 41-year long-term fertilization experiment，the effects of combined organic andinorganic applications on the fertility of dark brown soil and the yield and quality of spring wheat grains werestudied， and the relationship between soil enzyme activity and crop yield and quality under combined organic and inorganicapplication conditions wasanalyzed.The internal relationship provides a theoretical basis for the establishment of ascientific and reasonable organic and inorganic combined application technology system.The long -term positioningexperiment was carried out in 1979 and was located in Agricultural Academy in the Heihe City，Heilongjiang Province.The soil type was dark brownsoil.Six treatments were setup:control，low -quantityfertilizer，medium -quantityfertilizer，high -quantity fertilizer，organic fertilizer，organic fertilizer+medium -quantity fertilizer，soil samples(0～20cm)and wheat grain samples were collected in August2019.Five soil hydrolases，namely β -glucosidase， β-cellobiosidase，acetylglucosaminidase，acid phosphataseand leucine aminopeptidase enzyme activities were determinedand analyzed to study the changes of dark brown soil enzymeactivity，wheat grain yield andquality，and correlationanalysis wereconducted.Research indicatedthat:1)Compared with other treatments，the two treatments of single application of organic fertilizer and combined application of medium-quantitative fertilizer significantly improved soil β-glucosidase，β -cellobiosidase，acetylglucosaminidase，acid phosphatase and leucine aminopeptidase，and the activity of organic fertilizer combined with medium-quantitative fertilizer treatment was increased by 21.04%～95.74%， compared with the single application of medium-quantitative fertilizertreatment.2)The grain yield of wheat under differentfertilization treatments was significantly different.After fertilization，the wheat yield increased by 6.93%～ 111.03%compared with thecontrol.The single treatment of high -quantitative fertilizer and organic fertilizer combined with medium-quantitative fertilizer in the two treatments had a higher yield increaseratio.3)The grainquality，flour quality and doughquality of wheat all showed a consistent pattern.The comprehensive quality of wheat with organic fertilizer and chemicalfertilizer treatment was significantly higher than that with single chemical fertilizertreatment.4)There was a significantor extremely significant positive correlation between soil enzyme activity and wheat grainquality，flour quality and doughquality，and a positive correlation with wheatyield，but not significant.Soil enzyme activity and wheat yield and qualityunder different fertilization treatments were significantlydifferent.In the combined application of organic fertilizers and medium-quantitative fertilizer treatment has an obvious effect on improving soil enzyme activity，wheat yield and quality. The rational combination of organic fertilizers and chemical fertilizers is an important measure to improve soil fertility and obtain high-quality and high-yieldcrops.