The invention discloses an automatic material way assembly method. Firstly, material way parts are primarily assembled with left and right side plates of a material way; then, prepared left and right side punching plates with thimbles are respectively matched clamping jaws projected out of the left and right side plates of the material way at two ends of the material way parts; the thimbles arranged on the left and right side punching plates are corresponding to clamping jaw mounting holes on the left and right side plates one to one; and then, a hydropress is adopted to punch the left and right side punching plates, so that the clamping jaws are inflected to the corresponding left and right side plates under the stop effect of the root parts of the thimbles for flattening. Compared with traditional manual operation, the method greatly improves the production efficiency; machined material way products are excellent in consistency; the quality of the products is guaranteed; and the condition of flattening the clamping jaws by missing machining cannot be generated.