Abstract: The details of a new cryogenic water-trap for high vacuum applications based on a recuperative mixed-refrigerant refrigerator were disclosed. While used with a molecular turbo vacuum pump of 600 L/s pumping speed, the cryogenic water-vapor trap was driven by an oil-lubricated single-stage compressor with nominal input power of 450 W. The lowest temperature is 110 K. A comparison was made between a vacuum system with and without the cryogenic water-trap. The results show that the pumping down time of which with the cryogenic water-trap can be reduced greatly as ten times. This will be important for most vacuum systems, e.g. vacuum deposition system, semiconductor industry, etc. Compared with the traditional cryogenic pump, there is no requirement of periodic maintenance. Moreover, the new developed cryogenic water-trap has high reliability, low cost, and easy to be built in large scale based on numerous merits of mixed-refrigerant refrigeration system.