The embodiment of the invention discloses a method, device and system for indicating remaining capacity of a battery. The method includes the steps of obtaining a current remaining capacity of the battery; determining an output voltage to be output to the target component based on the current remaining capacity and preset correspondence information, wherein the preset correspondence information includes correspondence information between preset remaining capacity of the battery and the output voltage; controlling the battery to output the determined output voltage to the target component, so as to instruct the target component to determine the current remaining capacity of the battery based on the received output voltage and the preset correspondence information; and executing the corresponding operation according to the current remaining capacity. When the technical scheme is adopted, the battery matches well with the target component, and the target component can obtain the accurate remaining capacity of the battery according to the output voltage of the battery and perform the corresponding operation, thereby improving the use performance of the whole vehicle and user experience, and prolonging the service lifetime of the battery.