A vehicle burglar alarm system includes a global position system installed in a vehicle for receiving a satellite signal, and an on-vehicle main unit installed in the vehicle and electrically connected with the global position system, the on-vehicle main unit having a first flag, the first flag having a first status without satellite signal and a second status with satellite signal for indicating satellite receiving status of the global position system, the on-vehicle main unit being to output a relocation signal immediately after changing of the first flag from the first status without satellite signal to the second status with satellite signal during burglar alarming mode.