Civil air defense detection outer diameter measuring caliper

The utility model belongs to the technical field of civil air defense measuring calipers, and particularly relates to an external diameter measuring caliper for civil air defense detection, which comprises a measuring caliper body. A vernier slide ruler is slidably connected to the outside of the measuring caliper body, and size scales are arranged on the surface of the measuring caliper body. The bottom end of the vernier slide ruler is fixedly connected with a measuring clamping jaw plate. A positioning hole is formed in the vernier slide ruler; a positioning insertion rod is inserted into the positioning hole; the clamping jaw at the bottom end of the measuring caliper body is placed at one end of a workpiece, the positioning insertion rod is pulled to compress the positioning spring, the position of the vernier slide rule is limited on the measuring caliper body by the positioning insertion rod, and then the reading on the measuring caliper body and the vernier slide rule is read to obtain the outer diame