A device and system for detecting a touch panel are used for detecting a metal mesh on the touch panel, where row direction channels and column direction channels on the metal meshes each include a plurality of touch units which are connected with each other. In the device for detecting a touch panel, a signal transceiving component includes a signal generating unit and a signal receiving unit, which are configured to be arranged on the same side of the metal meshes in preset relative positions, and send and receive a signal through capacitive coupling with the metal mesh, respectively; a defect detecting unit is configured to detect each of a plurality of touch units in the metal meshes based on a detection signal received by the signal receiving unit.