Abstract: An experimental method for measuring the constitutive relation of granular flow was presented. Granular chute flow was described as a non-Newton fluid, and its constitutive relation was computed on the base of the velocity distribution calculated by the throwing motion of granules when being out of a chute. A model of granular chute flow was employed, which indicates that the velocity obeys exponential distribution and the flow rate is a function of chute angle and flow thickness. From the theoretical analysis of wheat granule chute flow by using the constitutive relation from experiment, the relative error of the predicted volume flow rate is less than 13% compared with experimental data.