Abstract: The Qaidam Basin is in the arid climate, and precipitation is very insufficient. Groundwater recharge is mainly from the river leakage. The calculation of the river leakage is the primary problem in the evaluation of groundwater resources. According to the characteristics of river leakage, an empirical equation that is applicable to the free leakage river is presented in this paper based on the analysis of the components of river leakage. The leakage ratios of the Golumd River, Tatalin River and Iqe River were calculated using the empirical equation. The results are similar to the measured leakage quantity, suggesting that the empirical equation has certain applicability and universality. Leakage ratio and leakage quantity of the main rivers in the Qaidam Basin were calculated. The result shows that the leakage ratios of the rivers with flow rate greater than 10m3/s are 61.1%~78.3%, whereas leakage ratios of the rivers with flow rate less than 5m3/s are 94.5%~99.9%. The result follows the general law of river leakage in the area. The leakage ratio equation developed in this study can be applied to areas with similar hydrogeological conditions.