Abstract: Helium Joule-Thomson(JT)cryocooler has become one of the mainstream technologies for space liquid helium temperature cooling.The typical helium JT cryocooler contains two power-consuming components:precooler and JT compressor.For space application of helium JT cryocooler,the total power consumption of the precooler and JT compressor is the key indicator.This paper takes the 100 mW@4.2 K JT cryocooler as the research object,and the minimum power consumption as the goal.By analyzing the minimum power consumption required by the cryocooler under the parameter combination of precooling temperature and high-pressure,the optimal operating parameters of helium JT cryocooler are obtained.Based on the two stage pulse tube precooler develop by the Shanghai Institute of Technical Physics,the total pow-er consumption of the JT cryocooler is calculated.The calculation results show that under the cooling target of 100 mW@4.2 K,when T_pre2 is 18 K,p_h is 1.85 MPa,the overall energy efficiency of the cryocooler is the highest,the total power consumption is 358 W,and the relative Carnot efficiency(rCOP) is 1.96%.The optimal operating parameter matching strategy can also be used to select the optimal operating parameters of a two-stage precooling large-scale JT device.