Electric surge protector of low-voltage distribution system, which is in the form of a box, is designed according to IEC standard. It has invalidation detection indication, lightning stroke numbering display, overflowing and overheating protection, and powerful discharge capacity of lightning current. It’s applicable to the protection of buildings’ general supply system against lightning, as well as Grade 1 and 2 lightning protection of the general supply building, machine room, plant and enterprise to make sure the safe operation of electronic equipment and other utilization equipment. This lightning arrester is very convenient to be maintained. It connects with the circuit in parallel and has no limit to the power of equipment fixed later.