Abstract: The key technology of gaining sandstone permeability from capillary pressure curves is the determination of Swanson parameter and Capillary-Parachor parameter. There exist many problems in conventional methods, including human factors affecting the result and slow velocity in calculation. Based on analyzing the shape of capillary pressure curves, a new method to automatically calculate Swanson parameter and Capillary-Parachor parameter by using cubic spline interpolation function is proposed. The accuracy of the new method is verified by comparing it with the conventional methods. 157 core samples from three different fields in western China with the permeability ranging from 0.002×10-3μm2 to 1150×10-3μm2 are selected to establish the relationship model between Swanson parameter and Capillary-Parachor parameter. After analyzing the models, the relationship between Swanson parameter and capillary-Parachor parameter calculated by the new method well coincides with sandstone permeability. The correlation between Swanson parameter and sandstone permeability is better than that of Capillary-Parachor parameter and sandstone permeability.