The invention relates to a plastic corrugated pipe forming machining method. The method mainly comprises the following steps: mixing and stirring, heating and drying, forming treatment, cooling forming, grain cutting, cutting operation and the like; and used corrugated pipe grain cutting equipment comprises a bottom plate, a rotating device, a clamping device and an abutting device. The followingproblems that during existing in existing corrugated pipe grain cutting, a, a production technology of traditional corrugated pipe manufacturing equipment is not mature enough, the operation is not stable enough, the grain quality of a corrugated pipe is seriously influenced, the corrugated pipe can only be manufactured through turning, but the wall thickness of the manufactured corrugated pipe isnot uniform easily due to the existing turning mode, and the service life of the corrugated pipe is shortened; and b, a traditional corrugated pipe forming machine is single in forming specification,the depth of corrugations on a pipe is low in the forming process, and the requirements in actual work cannot be met can be solved, corrugated pipe grains can be evenly and stably cut, and the production quality of the corrugated pipe is improved.