The distribution IoT network is the last link in the construction of the ubiquitous power IoT, which directly faces the users and is the bridge connecting power production and electricity users, affecting the safety and reliability of power supply. Since the distribution network has the characteristics of short power supply path and high load density, which leads to great difficulties in protection and control, it is urgent to establish a perfect distribution network early warning and self-healing strategy to form a smart distribution network with flexible operation mode, timely fault warning and perfect fault self-healing. This paper proposed a security defense technology framework applicable to the distribution IoT edge network and terminals, forms a technical scheme of distribution edge IoT with security warning and self-healing capabilities, and verified the feasibility of this scheme based on simulation experiments.