A field experiment with different fertilizing treatments was carried out to optimize the treatments which could improve both soil microbiological properties and crop yield.Soil urease,cellulase,microbial quantity and crop yield were analyzed.The results showed that the activities of soil urease and cellulase under the fertilizing treatments were all higher than that of control(p<005).Microbial quantity increased slightly under T5(conventional NPK+straw+straw decomposing inoculants)treatment compared with the others during the two seasons.The wheat yield under T5 treatment was the highest with a increase rate of 382%,but T3(07 conventional NPK+organic fertilizer)treatment was best for the corn yield with a increase rate of 292%.Correlation analysis concluded that,soil enzyme activity was correlated with crop yield and soil microbial quantity,respectively.To a certain degree,soil urease,cellulase activities could reflect soil fertility,and soil urease was related with microbial quantity in soil.The results above suggested that T5 treatment was most optimized for fertilizing under the experimental conditions.