A firmware overwriting method for paired use wireless microphone and receiver is disclosed. The firmware update method comprises building a wireless connection between the at least one wireless microphone and the at least one receiver; and executing the determining program by the receiver processing module to determine if the installed wireless microphone compatible backup firmware is the same as the wireless microphone firmware. If yes, the overwriting program is not executed. If no, the receiver processing module sends a command to the wireless microphone processing module to download the installed wireless microphone compatible backup firmware from the receiver storage module, and the overwriting program is executed by the wireless microphone processing module to overwrite the wireless microphone firmware with the installed wireless microphone compatible backup firmware.