The invention discloses a wet-strength wastepaper recycling double-pH-value chemical and mechanical pulping method. The method includes a material preparation section, a 
steaming section, a first 
extrusion and impregnation chemical and mechanical treatment section, a second 
extrusion and impregnation chemical and mechanical treatment section, a latency and re-defibering section and a purification, screening and concentration section. Wet-strength wastepaper 
fiber dissociation re-pulping is achieved while original pulp strength is not reduced through the mechanical strong force effect and the 
chemical treatment effect. Furthermore, on the two 
extrusion and impregnation chemical and mechanical treatment sections connected in series, a 
wet strength agent in wastepaper is oxidized under the acid condition firstly, 
hydrolysis is further promoted under the alkaline condition, chemical bonding between molecules of the 
wet strength agent and between the 
wet strength agent and pulp fibers is more effectively damaged, and the 
fiber dissociation rate and the re-pulping yield are effectively increased. The problems that the wet-strength wastepaper recycling pulping 
dissociation rate is low and strength is greatly decreased are solved, and continuous, large-scale, low-water-consumption and low-energy-consumption 
pollution-free and environment-friendly pulping can be achieved.