The invention discloses a multilayer-injection molding stepped mold device. The multilayer-injection molding stepped mold device comprises a bearing base; the upper surface of the bearing base is fixedly connected with a machining box; a movable mechanism is arranged on the lower surface inside the machining box; an injection molding mechanism connected with the movable mechanism is arranged inside the machining box; a traveling and fixing mechanism is disposed on the lower surface of the bearing base; a clamping and discharging mechanism which is in lap joint with the injection molding mechanism is arranged on the upper surface of the machining box; a group of stretching bars matched with a rotary shaft A are fixedly connected with the upper surface inside the machining box; and the lower end surface of each stretching bar is provided with a fixing round ring connected with the rotary shaft A. The multilayer-injection molding stepped mold device has the beneficial effects that the material cost and the machining cost are effectively reduced, meanwhile, the finished product rate and the production efficiency are greatly improved; and driving is reliable, ejecting is smooth, the size of a mold frame is greatly reduced, the mold space is reasonably utilized, and the mold device is convenient to observe and move.