The invention discloses a clean-free sewage lifting device. The device comprises a water collection box, wherein a side face of the water collection box is provided with a lifting adjustment valve; the lifting adjustment valve is connected with the water collection box through a flexible check valve; a liquid storage device is arranged in the water collection box, is fixedly arranged in the water collection box and is transversely provided with a sewage buffer pipe; one end of the sewage buffer pipe is connected with a floating valve; one end of the floating valve is connected with the sewage buffer pipe, and the other end of the floating valve is fixedly arranged on the inner wall of the water collection box; the lower surface of the floating valve is provided with a pressurization pipe; the pressurization pipe is in socket connection with the floating valve. According to the clean-free sewage lifting device, sewage can be discharged and can also be prevented from backflow; the device can be maintenance-free and clean-free; long-term effective safe operation is realized; the design and use requirements of underground toilets can be met better; the device has a compact structure, is stable in working and has a remarkable application value.