Abstract: The miniature Joule-Thomson cryocooler has been a popular device in the field of rapid cooling for many years.In this study，a steady-state physical model of Hampson-type J-T cryocooler with argon as the working fluid is established.The effects of the geometry parameters including fin height，fin thickness and fin pitch on the performance of the recuperative heat exchanger are studied using orthogonal experimental design.The results are studied by range analysis to get the rank of factors and the optimized combination.The heat transfer quantity increases by 7.31%and the effectiveness increases by 5.77%after the optimization.The model and results presented here provides a new approach for the design of J-T cryocooler.