The utility model discloses a bearing disassembling and assembling device for a multifunctional oil pumping unit, and belongs to the technical field of oil pumping unit accessories in oil exploitation. A base is connected with support frames and a guide chain frame; two pairs of support frames are symmetrically arranged on the base; the guide chain frame is connected with a guide chain; the support frames are connected with a pressing lever and a bearing support plate in a supporting way; the bearing support plate is connected with a middle shaft assembly; the middle shaft assembly is connected with a hydraulic jack; the support frames are provided with pressing lever holes. The bearing disassembling and assembling device has the advantages that when a tail shaft assembly and a crank pin shaft assembly in a pumping well need replacing, a bearing base is hoisted onto the device by using the guide chain, a damaged bearing is ejected out by using the hydraulic jack to prevent a middle tail shaft from being damaged in a construction process, and a new bearing is arranged in the bearing base finally. The middle tail bearing needs to be replaced by 3-4 persons in two hours before, and can be replaced by 1-2 persons in half an hour after the adoption of the device, so that the labor intensity of personnel is lowered, and a large amount of purchasing cost of the middle tail bearing assembly is reduced.