The invention discloses a wastepaper pulping and papermaking method, and relates to the technical field of testliner board. The method specifically adopts the devices such as a hydraulic pulper, a high-concentration desander, an unloading tower, a grading sieve slurry tank, a grading sieve, a filament first-stage slag remover, a filament multi-disk, a filament pulp tower, a bottom layer pre-papermaking tank, a staple grading sieve, a filament first-stage slag remover, a staple low-concentration desander, a staple multi-disc, a heat dispersion system, a staple pulp tower, a surface-layer pre-papermaking tank deduster, a bottom-layer headbox, a surface-layer headbox, a press section, a drying section, a sizing machine, a calender, a reeling machine, a re-reeling machine, and the like. The method has a high finished product conversion rate. With the method, 20000 tons of wastepaper can be saved per year, such that production cost can be reduced. Process parameters are optimized, such that unit product energy consumption is reduced, and energy is saved. Therefore, the production cost is further reduced.