The invention relates to a folding and pressing mechanism and belongs to the field of canvas installation and package. The folding and pressing mechanism comprises a fixing frame, folding air cylinders, a pressing device and a plurality of guide rod air cylinders. The fixing frame is provided with a cross beam. The guide rod air cylinders are uniformly installed on the cross beam. The left end and the right end of the cross beam are each provided with one folding air cylinder. The folding air cylinders drive the cross beam to rotate by 90 degrees. The pressing device is located above the folding air cylinders and fixed to the fixing frame and drives the guide rod air cylinders to achieve pressing action. According to the folding and pressing mechanism, the multiple guide rod air cylinders are adopted and can be used properly according to the width of a picture frame, the pressure of the guide rod air cylinders can be averaged to the greatest extent, and it is guaranteed that a canvas is pressed tightly and uniformly. The folding air cylinders are adopted, the function of folding the canvas manually is simulated, the design is ingenious, manpower is saved, the practicability is improved greatly,, and broad application prospects are achieved.