A method for displaying charge and gain energy by a vehicle solar roof system is provided. The method includes determining whether the vehicle is in a parking or driving mode based on whether the vehicle key is turned on or off when the solar roof system installed in the vehicle operates. A corresponding consumed energy is calculated by determining whether the solar roof system charges the auxiliary battery or the main battery. The consumed energy is displayed in the cluster of the vehicle and booting is performed when the key is turned on in the parking mode and displayed when the key is turned off in the driving mode. The consumed energy is calculated based on efficiency of a charge amount of the auxiliary battery or the main battery and a gain fuel amount is changed based on the charge amount and calculated due to the saved energy.