Flexible printed circuit and detecting device, detecting method and display device thereof

Disclosed are a flexible printed circuit and a detecting device, a detecting method and a display device thereof. The flexible printed circuit comprises a body and an interface structure that is connected with the body, wherein the interface structure is provided with a plurality of mark lines dividing the interface structure into a plurality of interfaces with the same structure. When a front end interface of the flexible printed circuit of the disclosure is damaged, the front end interface can be removed along the mark line, and then an exposed rear end interface can be used successively, thus preventing a situation where the flexible printed circuit cannot be used because the only interface is damaged, thereby extending the life span of the flexible printed circuit, reducing productivity loss due to frequent replacements of the flexible printed circuit and reducing production cost.