A marking-off and cutting device for a glass substrate comprises a workbench (1), a marking-off platform (2) mounted on the workbench (1) used for conveying a glass substrate, and marking-off mechanisms used for cutting the glass substrate. The marking-off mechanisms comprise a first marking-off mechanism mounted slidably on the workbench (1) along the conveying direction parallel to the glass substrate, and comprise a second marking-off mechanism mounted slidably to the workbench (1) along the conveying direction perpendicular to the glass substrate. The first marking-off mechanism has a first starting position and a first standby position, and the first marking-off mechanism can make reciprocating movement between the first starting position and the first standby position and can circularly mark off and cut multiple glass substrates conveyed by the marking-off platform (2). The device can implement the continuous operation of the marking-off and cutting, and improves the production efficiency for the marking-off and cutting on the premise of ensuring the marking-off and cutting quality.