The system with DS1302 as its clock makes one hour as one basic time unit, and thus there will be 24 monitoring segments in a day. It watches the movements of the aged through the sensors placed in the house-rooms such as bedroom, kitchen, and obtains the data of the movements and activities. Based on the data the MCU (Micro Control Unit) will make an hourly judgment whether the movements and activities are normal ones. When the system makes sure they are abnormal, it will dial out the setting telephone saved in EEPROM, waiting for the other end to pick up phone and then will send the tone alarm out. Once an accident happens, the alarm will be started up immediately by pressing the emergency button of the remote control. When the aged is out, he or she can shift the health mode to the away mode by the remote control, and the system will act as a home security system. In simulation experiments, the system works well at recognizing the data of movements and has a very low mis-alarm ratio. The system provides a viable solution to the social problem of looking after the aged who lives alone.