The invention provides a wireless resource management method which is applied to the multi-frequency network and the system thereof. The method includes steps as following: step 1, a wireless network controller sends the broadcast message along with frequency band direction message to a user device, so as to inform the user device of whether to detect different frequency subdistrict or not in surrounding, the user device submits the user device capacity message to the wireless network controller, wherein, the message which to support the multi frequency or not is added into the user device capacity message; step 2, the wireless network controller ensures whether to inform the user device of the possibly existent different frequency list according to different frequency distribution and the user device capacity message, if needing to inform, the different frequency subdistrict message and the measuring control message are added into the adjacent subdistrict list to send to the user device; step 3, the user device measures the different frequency subdistrict and sends the measuring result to the wireless network controller; step 4, according to the measuring result, the wireless network controller switches between frequencies, or dictates the user device to reelect the different frequency subdistrict.