The paper designed a system based on intelligence mega128 which can guard house against fire、thief and gas leak.The system ’s framework is composed of the advanced flammable gases sensor

pyroelectric sensors

gas leak detector

the regeneration of remote control module and peripheral device

the system has unlawful invasion caused police vehicles sound warning

discovery of fire caused the fire alarm sound

gas measurements can achieve digit display

calling Host cell phone alarm

automatically played out the fire for functions.Lifting alarms and working patterns are chosen by the wireless remote control.If the electricity fails

the system can also work properly by power supply module.The intelligent system is very economic and affordable.