A four-year(2015—2019)field experiment was carried out under wheat-maize rotation system in Langfangcity，Hebei province. The purpose of the experiment was to study how inorganic and organic amendments affecting nitrogencycling functional genes’abundance and extracellular enzymes. The experiment consisted of fourtreatments:control(CK)， inorganicamendment(SA)，organicamendment(SC)，and organic + inorganicamendments(SCA). After maize were harvested in2019，soil samples were collected from arable layer. Chemicalproperties，abundance of nitrogen cycling functionalgenes，and extracellular enzyme activities weremeasured. Soil integrated fertility index(IFI)was calculated using factor analysis method and Nemero index method. The results showed that amendments significantly increased the absolute abundance of soil nitrogen fixationgenes( nifH)，ammonia oxidizing bacteriagenes(AOB -amoA)，and denitrificationgenes( nirS and nosZ)(P<0.05). The abundance of functional genes was in the order of SCA>SC>SA. The redundancyanalysis(RDA)showed that soil organic carbon was the key factor affecting functional gene abundance.Furthermore， organic amendments significantly improvedcarbon(β -Glucosidase，β -Cellobiohydrolase)，nitrogen(β -1， 4-N-acetylglucosaminidase，leucineaminopeptidase)and phosphorus(alkaline phosphatase)related enzyme activities(P<0.05). RDA results showed that available phosphorus was the main factor affecting enzyme activities under different amendments. Soil IFIs using factor analysis method and Nemero index method were both positively correlated with maize yield.Inconclusion，combined application of organic and inorganic amendments could increase the abundance of functional genes related tonitrogencycling，and the activities of extracellular enzymes related tocarbon，nitrogen and phosphorus cycles， and improve thesoil IFI. Therefore，combined application of organic and inorganic amendments is an important strategy to promote nutrient condition and crop yield in sandy soil.