Installing lightning rod is an effective method to avoid lightning stroke. A metal rod is erected at the top of the house, the lower end of the rod is connected with a copper wire of sufficient thickness, and the lower end of the copper wire is connected with a metal plate and buried in a humid place deep underground. The upper end of the metal rod must be a tip or forked into several tips. With such a device, when there are charged clouds in the air. Due to electrostatic induction, the tip of the lightning rod concentrates heterogeneous charges, generates tip discharge, neutralizes with the electrical phase in the cloud, and avoids fierce lightning. This is one aspect of lightning protection of the lightning rod. However, this effect is quite slow. If the cloud accumulates electricity quickly, or a cloud with a large amount of charge suddenly flies, sometimes it is too late to neutralize in the above way, so there is a strong discharge, and the lightning will still occur. But at this time, because the lightning rod is higher than the surrounding objects, its tip concentrates the charge with different sign from the electricity in the cloud. If the lightning occurs between the cloud and the ground objects, the discharge current mainly flows into the earth through the lightning rod. Therefore, it will not hit the house or people nearby, but only the lightning rod. It can be seen that the tip discharge of lightning rod will reduce the possibility of lightning between ground objects and clouds; When it is inevitable, it bears the blow of thunder, and houses and people are safe. Due to the structure and function of lightning rod, we should pay special attention to maintaining the good conductivity of lightning rod. Once a connection is not good or broken, the section above the fracture becomes an isolated conductive system. When there are charges in the cloud, the upper part of the separated part induces charges with different numbers from those in the cloud, while the lower part induces charges with the same number as those in the cloud. If the upper part and the electricity in the cloud discharge, the strong discharge current can only release a large amount of heat through the building, resulting in lightning stroke. This will not only prevent lightning, but also cause lightning disaster. In order to prevent accidents, it is best to erect several lightning rods in tall buildings. In addition, each lightning rod can only protect a certain building area. For larger buildings, several lightning rods also need to be erected.