A wireless control system and a wireless network expansion method applied thereto are provided. The wireless control system comprises a mobile platform and a plurality of wireless devices capable of switching between a first role and a second role. The wireless network expansion method comprises following steps. A mobile platform is turned on. The mobile platforms scans the wireless devices and links to any wireless device serving the first role and then sends a control command to corresponding wireless device, which accordingly broadcasts the control command. The control command is received by at least one wireless device serving the second role. The wireless devices cyclically switch between the first role and the second role to continuously broadcast the control command to other wireless devices serving the second role, so that all of the wireless devices can finally receive the control command from the mobile platform.