The invention discloses a dividing joint slotting process. The dividing joint slotting process comprises the following steps of S1, pulling out tendons; S2, smearing decorative mortar for leveling; S3, scraping fine particles for repairing and leveling; S4, scraping the texture for the first time; S5, snapping lines and dividing grids; S6, slotting by a slotting machine; S7, scraping the texture for the second time and digging out seams; S8, texture polishing and grinding; S9, printing; S10, spraying points; S11, polishing a surface layer; S12, brushing finish-coat paint; S13, pasting a paper adhesive tape; S14, carrying out seam tracing; and S15, tearing the paper adhesive tape. By adopting the process, the working hours are greatly shortened, the working efficiency is improved, the quality is effectively improved, the flatness of a finished surface and the straightness, uniform size and consistent depth of the seams are ensured, and the cost of a thick paper adhesive tape is saved.