The invention discloses a simple pressure feeding well mouth protecting device. The device comprises a feeding device upper structure and a feeding device lower structure. The feeding device upper structure mainly comprises an upper joint pipe, a feeding pipe, a feeding inner layer pipe lock sleeve, a feeding outer layer pipe lock sleeve, a blowout prevention sealing shaft, a blowout prevention sealing shaft lock sleeve, a fixed beam lock sleeve, a protective sealing pipe and an oil pipe packer module; and the feeding device lower structure mainly comprises a movable beam, a movable beam lifting connecting hole, a movable beam positioning bolt, a fixed beam, a fixed beam middle through pipe and a double-stage hydraulic cylinder. The device is simple in structure, safe and reliable, can isolate the Christmas tree upward hanging, improves the ground construction pressure limiting during pumping, reduces the reservoir pollution caused by the well control operation, and guarantees excellent oil field development effect.