The invention discloses a method for printing a plastic film through an offset printing press, a finished product and a product. Firstly, roll paper and a plastic film roll are fed onto an adhesive rolling machine or an adhesive spraying machine to complete adhering of the roll paper and the plastic film roll; then, flattening, airing and transverse cutting are performed to form to-be-printed paper with the plastic film on one face in a one-piece state; next, the to-be-printed paper is fed onto the offset printing press to complete printing of the face of the roll paper or the plastic film roll, so that finished product one-face film covering paper with one-face printing is obtained; finally, the finished product one-face film covering paper is used for manufacturing a needed environmentally-friendly packaging bag or packaging box. In this way, the plastic film or the paper covered with the plastic film is fed onto the offset printing press to be printed, the problem is solved that inthe prior art, gravure is solely adopted for a soft plastic film, and the soft plastic film can not be fed onto the offset printing press, and the method has the advantages that costs are low, environmental protection is realized, printing speed is high, efficiency is high, color rendition is good, and a life-like effect is realized; the mode of plastic packaging is enriched, the grade of packaging is increased, and the requirement for really sustainable, healthy and environmentally friendly development is met.