Ship three-line centering measuring caliper

A ship three-line centering measuring caliper comprises a straight ruler engraved with linear scale, a side plate and a clamping plate; and the side plate and the clamping plate are located on the same plane, the side plate extends from an end portion of the straight ruler, and the clamping plate extends from an end portion of the side plate. The ship three-line centering measuring caliper is a fixed overall tool, has the advantages of high measuring precision, simple structure and small size, can greatly simplify work, and can improve operation convenience and working efficiency; requirements of matching equipment and manpower are reduced at the same time, and production cost is lowered; and the ship three-line centering measuring caliper can also be applied to various positions and structures on a ship, do not need to manufacture specially-made templates in quantity, greatly reduce resource consumption, production cost and the management difficulty, and improve on-site environment.