The invention discloses a carton lining plastic bag preparation technology which comprises the following steps: a low-density high-pressure polyethylene film is selected, the size of the film is determined as demanded, the film is folio, two squares are cut off at two angles on one side of the line made by folding according to the length of one half of the bottom width of a plastic inner bag, the cut-off film is opened and is erected along the cut-off lines to form a three-dimensional square bag shape, the horizontal sides and central vertical sides at the bottoms of two side faces are sealed, and eyelet work is carried out on long sides and narrow sides of the inner bag as demanded. According to the invention, the sealing sides of the carton lining plastic bag are decreased to four sides, so that the production processes are reduced, the raw material is saved, investment in labor force and the production cost are reduced, and the production efficiency is improved; and in addition, the product is uniform and transparent in color and luster, is free from extraneous odor and foreign matter, and is higher in quality level.