A check valve which is a critical component for cryogenic sorption compressor, has been developed previously by several researches. Its leakage rate was phenomenologically explained by the model of Poiseuille flow with the effect of pressure difference or temperature. This paper specifically investigates the leakage rate of the metal-to-metal check valve at 20 K, 77 K and 294 K in the situation of the back pressure from 150 kPa to 1,450 kPa. The leakage flow phenomenon is analyzed in more detail at various temperature, pressure difference and flow regime. Since Poiseuille flow which was adopted by previous researches cannot comprehensively reflect the effect of temperature and the pressure difference, the transition flow model has been subsequently employed to predict the leakage rate at 20 K. The leakage rate at 20 K is well predicted by using the 77 K and 294 K results with maximum and minimum approximation error of 22 % and 3.5 %, respectively. Uncertainty analysis is conducted to ensure the reliability of the prediction results. Furthermore, the allowable leakage rate of the check valve according to the ratio of the actual and ideal mass flow rates of the sorption compressor are derived.