The utility model provides a measuring ruler, which comprises two graduated scales hinged through an articulation piece, and the articulation piece is connected with an angle sensor device; one graduated scale is sleeved with a first sliding piece in a sliding mode, and a displacement sensor device is fixedly arranged on the first sliding piece; a second sliding piece is arranged on the other graduated scale in a sliding and sleeving manner; the first sliding piece and the second sliding piece are correspondingly provided with matched installation parts, the installation parts comprise the first installation part and the second installation part, and a vernier scale is installed on the installation parts. According to the vernier caliper, the installation part is arranged, so that the vernier caliper can be fixed on the installation part when not used for measurement, and the vernier caliper is convenient to use; during measurement, the vernier scale is fixed to the first installationpart and the second installation part at the same time and used in cooperation with the angle sensor device and the displacement sensor device, the size, the width and the height of a bulge can be conveniently measured, and the depth of a pit can also be measured.