Studies on the characteristic of ammonia volatilization in soil surface applied urea,compound fertilizer,coated urea and coated compound fertilizer by the enclosure method.The results indicated that ammonia volatilization characteristic of secondary processing urea were different:(1)9.2%,10.4%,7.6%,9.3% of total applied N were volatilized when urea,compound fertilizer,coated urea and coated compound fertilizer were applied.(2)The amount of ammonia volatilization of compound fertilizer was 12.9% higher than that of urea.(3)Coated urea ammonia volatilization was 17.9% lower than urea.(4)The amount ammonia volatilization of compound fertilizer were close to than that of urea.Though coated compound fertilizer ammonia volatilization was 15.6% lower than that of urea in the 25 day after surface applied,20.7% higher than of urea in the last 25 day.(5)The ammonia volatilization characteristic of secondary processing urea was need further studies with its production process.