Chainsaw spark plugs have the same composition as commonly used automobile spark plugs. They are divided into two major parts according to material: insulator and metal shell; according to structure, they are divided into three parts, namely, local electrode, steel body and radial electrode, and insulating ceramic core. The upper part of the steel body is made into a hexagon for easy disassembly and assembly with a wrench, and the lower part has screw threads that can be screwed into the cylinder head. The metal shell has threads for screwing into the cylinder; an insulator is installed inside the shell, with a center electrode running through the outside, and a wiring nut on the upper end of the center electrode to connect the high-voltage wires passing from the distribution board; on the shell A ground electrode is welded to the lower end face, and there is a gap of 0.6-1.0 mm between the center electrode and the ground electrode. When high-voltage electricity passes through this gap, sparks will burst out to ignite the mixed gas.