An input device with a dynamic display function includes a panel, an interface unit, and a control module, with multiple buttons groups randomly mounted on the panel. Each buttons group has at least one button, and one buttons group has at least two buttons. Every button has a lighting unit placed adjacently and has a symbol marked thereon, and the buttons in the same buttons groups have an identical symbol. The control module is electrically connected with the interface unit and the lighting unit and lights up at least one lighting unit and its corresponding button in every buttons groups. The interface unit transfers a signal from the lit button when the button is triggered. The buttons are randomly lit up by the control module in every operation.