A wireless tire pressure alarming system includes a tire pressure sensor & transmitter attached to each car wheel for sensing the tire pressure in each car wheel and for remotely sending the tire pressure signal from each car wheel; and a receiver having a plug plugged in a car cigarette-lighter receptacle to be powered by the car battery through such a cigarette-lighter receptacle and for receiving the tire pressure signal from the car wheel; whereby upon detection of a tire pressure reduced below the pre-determined safety pressure value of each car wheel, an alarm will be actuated either by an optical alarm signal or a sound alarm signal for warning the car driver for inflating his or her car wheel for enhancing driving safety.