Abstract A 2-cavity two-plate mold was designed for injection molding of plastic parts of 135° elbow pipe of injection molding machine. Mold uses 4 types of demolding mechanisms for demolding of molded plastic parts, including bend pipe, straight pipe, retractable, push rod ejection and other demoulding mechanisms. Elbow core pulling mechanism uses a rack to drive sector gear, then arc slider is driven to perform rotary core pulling; straight tube core pulling mechanism uses a hydraulic cylinder to drive inner and outer wall cores to perform 2 core pulling; inner core pulling mechanism uses T-slots locking block to drive inner retractable core pulling; plastic part is finally pushed out by push rod.