An exemplary embodiment of a method illustrates a gain control method executed in a wireless signal receiver. The gain control method has the following steps. A wideband channel is continuously monitored to check whether an interference signal exists in a wireless signal. When the interference signal exists in the wireless signal, an interference received signal strength indicator is obtained. A front end gain of the wireless signal receiver is controlled according to the interference received signal strength indicator. When the interference signal exists in the wireless signal, the wireless signal receiver is prohibited from using a maximum front end gain.