A wireless keyboard comprises at least a keystroke each comprising a first resonating circuit for responsing a first wireless signal to provide a power source, a chip storing a key data, and a switch coupled between the first resonating circuit and the chip for conducting a connection between the first resonating circuit and the chip when receiving an external force, to transmit the power source provided by the first resonating circuit to the chip, such that the chip outputs the key data as a second wireless signal via the first resonating circuit, and a reader coupled to a computer system for emitting the first wireless signal to the each keystroke and responsing the second wireless signal outputted by the each keystroke, so as to determine commands inputted to the computer system.