This work includes four modules: intelligent door lock, mobile phone terminal, remote control terminal and external control terminal, which greatly optimizes the call-for-help process for the elderly when emergencies come, and at the same time avoids the impact of unexpected situations such as power failure and limited movement of the elderly on the rescue work. Its main body is the external control terminal of the intelligent door lock based on the Arduino development board, which is the expansion module of the intelligent door lock. Its functions are: receiving the door lock switch control signal from the mobile phone terminal, the door lock switch control of the remote control terminal and the emergency call signal. If it is a door lock control signal, it will send an unlock or close signal to the intelligent door lock according to the signal content. If it is an emergency call signal, then, an unlocking signal is sent to the intelligent door lock and a distress signal is sent to the mobile phone end, and the basic physical information of the elderly and the help signal are sent to the bound contact in the APP. The smart door lock can control the opening of the door lock by inputting high and low levels to the unlock signal interface, and control the closing of the door lock by controlling the on-off of the lock signal interface. The mobile phone terminal realizes interaction with the user, which is used to remotely control the door lock switch, detect the distress signal of the elderly and call for emergency help, so that the elderly can get timely help when they are in danger. If the mobile phone is nearby and the consciousness is not clear when the old man is in danger, the APP detects in the background that the old man knocks on a hard object with the mobile phone, which will passively trigger the unlock and call contact functions. The remote control terminal is used as a standby emergency terminal for remote control of the door lock switch and emergency call for help, in case of emergency when the mobile phone is not around the elderly, it can also help the elderly in time;