The invention discloses a diaphragm type air pressure gauge, which comprises a material delivery pipeline, flanges are fixedly connected to both ends of the material delivery pipeline, and a first protective frame is fixedly connected to the top of the flange. The top of the feeding pipeline is communicated with a connecting pipe, the top of the connecting pipe passes through the bottom of the first protective frame and extends to the inner cavity of the first protective frame, the top of the connecting pipe is provided with a pressure gauge head, and the pressure gauge The inside of the head is provided with a pressure pointer. The present invention can protect the pressure gauge by setting the second protective frame, the first insert plate, the second insert plate, the threaded hole, the threaded rod, the movable groove, the clamp block, the rotating handle, the limit groove, the limit block and the clamp groove. It has a good protective effect, and it is more convenient to use. It is not easy to be accidentally touched during use, which ensures the safety of the pressure gauge, ensures the normal use of the pressure gauge, and even avoids the problem of material leakage inside the pipe body. Appear.