The invention provides a preservative treatment method for brassica rapa pekinensis. The preservative treatment method comprises the following steps of: sterilizing brassica rapa pekinensis with a bactericide mixed liquid, wherein the bactericide mixed liquid comprises sodium hypochlorite and dimethyl carbonate, the mass content of active chlorine in sodium hypochlorite in the bactericide mixed liquid is 0.2-0.8PPM, and the volume content of dimethyl carbonate in the bactericide mixed liquid is 200-300mu L/L; packaging the brassica rapa pekinensis subjected to sterilization treatment by using a preservative bag; and performing cold chain storage and transportation on the packaged brassica rapa pekinensis. As a sterilization mode of sodium hypochlorite together with dimethyl carbonate is adopted in the preservative treatment method provided by the invention, relatively thorough sterilization can be achieved, and the shelf life of brassica rapa pekinensis can be prolonged for 1-2 days; the shelf life of the brassica rapa pekinensis can be further prolonged for 1-2 days due to the cold chain storage and transportation mode, the shelf life of an ordinary fresh-cut product is only 6 days, so that the shelf life can be remarkably prolonged by at least 30% due to the preservative treatment method.