The design of inflation parameters were discussed after that the design of general structure and the bellow of cooler were determined.The advantages by using argon as inflation refrigerant were analyzed theoretically.The experiments prove that argon can effectively improve the starting time and the temperature control precision of J-T cooler.The calculation method of the minimum reservation amount and the minimum inflation pressure were determined by force analysis of self-regulated mechanism.The inflation pressure of some type cooler was determined by experiment.