Abstract: Stirling/pulse tube hybrid cryocooler is a new cryogenic refrigerator proposed. It overcomes the defects of vibration interference of Stirling refrigerator and low refrigeration efficiency of pulse tube refrigerator in deep low temperature area, and can meet the demand of dynamic load refrigeration.It has great potential in space application of refrigeration technology in deep low temperature area.The Stirling/tube hybrid cryocooler model was established by using simulation software. By adjusting the length of regenerator and the displacers phase, the distribution of thermal parameters in the hybrid cryocooler and the variation of the efficiency of the refrigerator with different displacers phase were investigated. The results show that the cooling capacity distribution of two stages can be adjusted by controlling the displacers phase actively. When the lengths of the second stage regenerator is 35 mm and the displacers phase is about 110°, the cooling capacity is 0.93 W at 20 K.The mass flow at the hot side of the second stage regenerator is 23.4° ahead of the pressure wave, and the mass flow at the cold side is 21.7° behind, and the reasonable phase distribution can be obtained.