The invention discloses a working method for a grabbing and conveying mechanism for plastic plates. According to the working method, the grabbing and conveying mechanism for the plastic plates comprises a placement barrel body and a conveying frame, wherein the conveying frame is located on the right side of the placement barrel body; a placement inner cavity is formed in the middle of the placement barrel body; vertical through grooves are formed in the inner side walls of the placement inner cavity; lifting air cylinders are fixed to the outer side walls of the lower part of the placement barrel body; lifting blocks are fixed to the end parts of push rods of the lifting air cylinders and are inserted into the corresponding vertical through grooves in a sleeving mode; a bottom supportingblock is fixed in the middle of the bottom surface of the placement inner cavity; the multiple plastic plates are stacked on the bottom supporting block; the end parts of the lifting blocks are located on the bottom surfaces of the edge parts of the plastic plate at the bottommost part; supporting plates are fixed to the two opposite outer side walls of the placement barrel body; an upper connecting plate is fixed to the two supporting plates; and the right end of the upper connecting plate is located right above a material receiving disc of the conveying frame. The working method has the advantages that the plastic plates can be automatically grabbed and can be automatically conveyed, feeding can be facilitated, and the production efficiency can be improved.