Crack width change monitoring device

The utility model discloses a crack width change monitoring device, and relates to the crack monitoring technology in engineering mechanics. The monitoring device comprises a monitoring region (00), a left side identification plate (10), a right side identification plate (20), a mobile phone (30), a transmission line (40) and a computer (50). In the monitoring region (00), the left side identification plate (10) and the right side identification plate (20) are arranged at the left side and the right side of a crack (11). The mobile phone (30) takes a picture of the monitoring region (00). The mobile phone (30), the transmission line (40) and the computer (50) are connected in order. The carry-on mobile phone is employed to scan a two-dimension code and take a picture, the monitoring device is convenient to carry, is convenient to operate, and raises the monitoring efficiency. The picture is sent to the computer and the crack width monitoring result is calculated. The monitoring precision is high, the economical effects are remarkable, and the monitoring device is easy for popularization.