In order to improve the security of home, an intelligent home security alarm system based on Micro-programmed Control Unit (MCU) has been designed in this paper, which can monitor the doors and windows, and communicate with intrusion alarm system by using GSM. Practical measured results indicate that this system can complete the function of home security alarm, which has a strong practical popularize value.In order to improve the security of home, an intelligent home security system based on MCU has been designed in this paper, which realizes en-mg checking, password storage, sound/short message warning service and real-time monitoring through GSM network. The hardware and software designs are illustrated in the paper. Finally, the test is carried out and the results indicate that the functions of system have achieved the design goal.