Field experiment was conducted to study the effects of applying 30% coated controlled release urea of 60 d release duration mixed with 70% common urea by different applying methods,ie.sidedressing,bottom application and layer by layer application,on soil urease,net photosynthetic rate and protective enzymes activity of spring maize leaves with none Nfertilizer used(CK)as control.The results showed that under the same Nfertilizer supply,the soil urease under bottom application was significantly higher than those of sidedressing and CK,especially at tasseling and filling stage,but no significant difference of the urease at 0~40 cm layer between bottom and layer by layer applications was observed.Compared with layer by layer application,sidedressing and CK,the means of soil urease under bottom application was increased by 4.03%,55.94% and 58.01% at 0~20 cm layer,and increased by 3.77%，57.07% and 67.37% at 20~40 cm layer,respectively.The total N content in plant and grain among different treatments presented the same trend:bottom application>layer by layer application>sidedressing>CK.At tasseling and filling stage,compared to layer by layer application,sidedressing,CK treatment,the leaf net photosynthetic rate under bottom application was increased by 3.61%,11.42% and 33.43% respectively.In the meanwhile,CAT,SOD and POD activities of leaves were improved under bottom application.In addition,compared to layer by layer application,sidedressing,CK,maize yield under bottom application treatment was increased by 0.42%,5.81% and 49.23%,respectively.Therefore,the bottom application of the coated controlled release urea mixed with common urea with low cost and obvious effect,is suitable for promotion in Beijing area.