A battery-free remote controller includes an antenna, a plurality of key switches, and at least one electronic tag. The antenna is electrically connected to the plurality of key switches, and each electronic tag is electrically connected to the antenna through at least one of the key switches. Each electronic tag is corresponding to a device classification code, and each key switch is corresponding to an operation code. When one of the key switches is turned on, the electronic tag connected to the key switch is electrically connected to the antenna. At this time, the electronic tag uses a radio frequency signal received by the antenna as a power supply to output a remote control code containing the device classification code corresponding to the electronic tag and the operation code corresponding to the key switch, and the antenna transmits the remote control code.