To explore the nitrogen transformation and ammonia volatilization of UAN nitrogen solution and its respective application with N-butyl thiophosphoric triamide(NBPT)on gray desert soil，fluvo-aquic soil and red soil，an indoor constant temperature incubation experiment was conducted to determine the dynamics of nitrogen transformation and ammonia volatilization when UAN nitrogen solution was applied in combination with NBPT.The results show that:(1)UAN nitrogen solution could provide 0%～46.67% more inorganic nitrogen supplies than urea during 6 h～7 d after fertilization.In the fluvo-aquic soil and gray desert soil，the ammonia volatilization of the UAN nitrogen solution was significantly higher than that of the urea，but there was no significant difference in the ammonia volatilization between them on the red soil.(2)In gray desert soil，fluvo-aquic soil and red soil，the urease inhibition rates of NBPT were 5.20%～34.29%，4.10%～38.02% and 3.27%～33.96%，respectively，and the inhibitory effect on fluvo-aquic soil and gray desert soil was better than that of red soil.NBPT reduced the nitrate nitrogen content in fluvo-aquic soil during 14～28 d，the apparent nitrification inhibition rate of the solution was 30.94%～31.42% when NBPT combined with UAN nitrogen.(3)NBPT reduced the ammonia volatilization rate，ammonia volatilization accumulation and total ammonia volatilization after nitrogen application in three soils.NBPT combined with UAN nitrogen solution reduced the total ammonia volatilization by 14.89%～21.20%，the largest figure was on fluvo-aquic soil，reaching 21.20%，the smallest figure was on gray desert soil，which was 14.89%.(4)As to different dosages，there was no significant difference for the inhibitory effect of 0.8‰NBPT and 1.5‰ NBPT on gray desert soil and red soil.The inhibition effect of 1.5‰ NBPT was significantly greater than that of 0.8‰NBPT on fluvo-aquic soil.Considering both the application effect and economic benefit，the application of 0.8‰ NBPT with UAN nitrogen solution is the optimal combination.