A wireless tire pressure monitoring system includes a monitoring main unit installed in the truck-tractor of a towing vehicle, a receiving antenna electrically connected to the monitoring main unit, and a register set in a location within the wireless communication transmission range of the receiving antenna and stored with an ID code and location code of each sensor at each wheel of the platform of the towing vehicle. When the register receives a triggering signal containing an identification code of the monitoring main unit, the register compares and matches the identification code and the location code of every wheel of the platform with the identification code of the monitoring main unit and then sends matched data in the form of a wireless packet to the receiving antenna for enabling the monitoring main unit to recognize the installation location of every wheel of the platform of the towing vehicle.