Abstract: This paper introduces the burglar alarm systems in home basing on the SMS module of GSM. The design of hardware and software, the choice of components, and the design of unit circuits and the circuit connection of the system are described. The system used on STC company production of low-power microcontroller STC12LE5A60S2 as the processor,SIMCOM SIM900A module as a wireless co mmunication module, and through infrared sensing module and microwave sensor module invasion of signal monitoring, when the two modules to detect intrusion signals at the same time, by SMS alarm to the outside world and realize the remote alarm functions. Finally,practice has proved that the system is reliable and low cost,which can be widely used in modem houses.