The invention discloses an automatic grabbing and lifting mechanism for a plastic barrel. The automatic grabbing and lifting mechanism comprises a machine frame. The middle of a top plate of the machine frame is provided with a placement through hole. An annular guide body is inserted in the placement through hole in a sleeved mode. The middle of the outer side wall of the annular guide body is provided with an annular groove. The inner wall of the placement through hole is inlaid in the annular groove. A grabbing frame is fixed to the top plate of the machine frame. A grabbing air cylinder is fixed to a top plate of the grabbing frame. A push rod of the grabbing air cylinder penetrates through the top plate of the grabbing frame and is fixedly provided with a grabbing connection plate. An annular cover is fixed to the bottom face of the grabbing connection plate. A clamping air cylinder is fixed to the outer side wall of the annular groove. A push rod of the clamping air cylinder penetrates through the annular cover and is fixedly provided with two arc clamping blocks. The two arc clamping blocks correspond to the outer side wall of the top of the plastic barrel to be processed. By the adoption of the automatic grabbing and lifting mechanism, the plastic barrel can be placed and automatically lifted, meanwhile, the plastic baffle can be automatically grabbed and placed, the outer wall can be painted conveniently, efficiency is high, and the effect is good.