The invention discloses a chemical mechanical pulping method which uses cotton stalk as material, wherein the invention processes the first grinding after the first screw protrusion pre-immersion to replace present APMP technique which comprises two screw protrusion immersion followed with at least two sections of grinding, then holds the pulp after first grinding process for some time to process chemical reaction, at the same time, the invention uses novel additive to replace traditional metal ion chelating agent, Na2SiO3 and MgSO4. Compared with present APMP technique, the invention has low cost and high strength to be used to produce high-level paper.