Unpowered ammonia recovery unit is a new energy saving and environmental protection technology device for recovering the gaseous ammonia in purge gas of synthetic ammonia. The principle, the technological process, the main characteristics of equipments, the indicators and the operation conditions of the technology in Hebei Jinyuan Chemical Shares Corporation Ltd. were introduced. It was showed that all the temperatures and pressures were in the design range, the ammonia recovery rate was 98%, the amount of ammonia in exhaust gas was less than 1.1%, the year ammonia recovery was about 3 500 t, and the annual benefit was 3.5 million yuan.