A vehicle-mounted display device comprises a display mounted to a shaft, and operable to revolve with the rotation of the shaft; a transmission mechanism for coupling an output shaft of a motor with the shaft; a control module for controlling the motor; a baffle plate located at any position that enables it to rotate in synchronism with the rotation of the display, and a detection module for detecting the baffle plate. During the rotation of the display, when the detecting module does not detect the baffle plate in a predetermined period of time, the control module causes the motor to stop running or to turn in a reverse direction. This vehicle-mounted display device not only is reliably operable and electronically controllable, but also has anti-clamping and self-protection functions and has a simple structure and low cost.