Based on the Carman-Kozeny-Blake model and the contracting-expanding channel model, this study developed a new resistance model for predicting power law fluid flow through granular porous medium with homogeneous spherical particles. For the rheological properties of power-law fluid, by employing the average hydraulic radius theory, a modified Ergun type equation was expressed as a function of tortuosity, porosity, ratio of pore diameter to throat diameter, diameter of particles, and fluid rheological index. Every parameter such as A and B in the proposed model had clear physical meaning. The validity of the present model was evaluated by comparing the predicted friction factor to the published theoretical models and the experimental data correlations, the analysis results showed that the new model predictions were in good agreement with the existing documents data in a certain regime. At last, to further understand the flow resistance characteristic, the correlations of critical Reynolds number, the modified permeability and the inertia coefficient for power law fluid were also expressed.