The utility model discloses an ammonia refrigeration system, including utilize the pipeline connect gradually the cyclization be used for with evaporimeter by the refrigerant heat exchange, be used for inhaleing the ammonia the compressor, be used for becoming the ammonia condensation condenser of liquid ammonia and being used for throttling high -pressure liquid ammonia for the choke valve of low temperature and low pressure liquid ammonia, be provided with ammonia oil separator between compressor and the condenser, ammonia oil separator includes the knockout drum body, advances the ammonia pipe, goes out the ammonia pipe, advancing ammonia pipe one end and being connected with the compressor, the other end physically extends that into the knockout drum is internal in the top by the knockout drum to sensible its lower part, play ammonia pipe one end is connected with the condenser, and the other end physically is connected on upper portion with the knockout drum, still include the play oil pipe who manages and be connected with separation tank connection's benefit ammonia bottom the knockout drum body. The ammonia refrigeration system who has above -mentioned structure, its ammonia oil separation does not have moving part, simple structure separating of oil combination reasonable, that carry out the multistep to guarantee reliably thoroughly to come out the separating of oil, thoroughly stops the oily condenser that gets into and forms the oil film.