Abstract: A kind of venting method was designed to determine ammonia volatilization from soil in field, and proved by recovery tests and field experiments The obtained results showed that compared with traditional enclosure method, the venting method was simple in structure, easy to operate, and high in accuracy and precision with a recovery of 99.51% and a variation coefficient of 0.77% The average volatilization rates and the total amounts of volatilized ammonia determined by the venting method ranged from N 0.07 to 0.87kghm-2d-1, and from N2.93 to 35.69 kghm-2d-1 respectively, which were significantly higher than those determined by the enclosure method for the plots with different N rates Therefore the venting method was more suitable for in situ determination of ammonia volatilization in field