The invention discloses a buffering and transferring device for machine tool assembly line machining of spindle parts. The buffering and transferring device comprises a bottom plate, a guide rail, rollers, roller shafts, bearings, bearing end covers, a motor support, a servo motor, a coupler, a lead screw, a mounted bearing, a bearing seat support, a nut seat, a movable support, an air cylinder, a guide rod, a bracket, a robot, a magnetic type part taking device, a binocular camera, a binocular camera support, a part base plate, a temporary storage frame and a positioning pin. According to the buffering and transferring device, automatic feeding and discharging of spindle part assembly line machining are achieved, manual carrying is avoided, automatic workpiece state detection and automatic size detection are achieved, automatic feeding, discharging and storage are achieved, the requirement for simultaneous machining of multiple machine tools can be met, transferring, feeding and discharging of materials among the multiple machine tools are achieved, technical support is provided for an unmanned intelligent production line, the intelligent level of a workshop is improved, and technical support is provided for realizing a digital workshop.