Taking long-term positioning test in loessal soil of National soil quality stability observation and test station in Anding District of Gansu Province as the researchobject，the effects of long-term organic manure application on yield and water use efficiency of spring wheat and soil organic carbon in semi-arid area were explored. The results showed that fertilization had significant impact on yield and water useefficiency of springwheat，and the effect of combined application of organic manureand chemical fertilizer(NPKM)was the best，compared with treatmentsof chemical fertilizer(NPK) and organicmanure(OM)，the yield and water use efficiency of spring wheat for NPKM were increased by 7.18% and 7.82%，5.91% and3.83%，respectively，after seven years continuous planting of wheat. In the early stage of fertilization(the first threeyears)，the effect of NPKM and NPK treatments werebetter than that of OMtreatment，and there was no difference among the three treatmentsin the fourth year of continuous locationfertilization，but the effect of NPKM and OM treatments were obviously better than that of applyingchemical fertilizer(NPK)in the fifth year and after. Compared withNPK treatment，the content of organic carbon of long -term NPKM and OM treatments were increased significantly by 36.88% and 31.98% in 0-20 cmsoillayer，and organic carbon reserves were increased significantly by 31.17%-41.94% and 27.80%-35.81%，respectively，and incremental effects of 0 -10 cm surface layer was significantly better than that of 10-20 cm. The effects of different fertilization treatments onsoil microbial biomass carbon(MBC)were asfollows:NPKM>OM>NPK>CK， there wassignificant difference betweentreatments，and soil MBC of NPKM and OM treatments were increased significantlyby 46.4% and28.7%，respectively，compared with NPK. Long -term single application of NPK could significantly improve the contentofMBC，however，it had no obvious effect onthe content of organic carbon. Inconclusion，long -term NPKM or OM treatments can significantly increase the contents of total organic carbon and microbial biomass carbon of the loessal soilindryland，and increase organic carbon storage and promote the sequestration of farmlandsoilcarbon，and improve yield and water use efficiency of spring wheat.