Spark plug

A spark plug disclosed by the present invention comprises a spark plug shell fixedly connected with an insulating assembly, the insulating assembly wraps a central electrode, and a hollow cavity is arranged in the spark plug shell. The insulator tip of the insulating assembly is arranged in the hollow cavity and is equipped with an ignition end part, the central electrode is connected with the ignition end part, a central hole having the effect of a one-way valve is arranged in the middle part of the end face of the spark plug shell relative to the other side of the insulating assembly, and anexhaust hole communicated with the hollow cavity is arranged at the outer edge of the end face of the spark plug shell relative to the other side of the insulating assembly. According to the presentinvention. A hole-shaped electrode is formed via the central hole, at the same time, the central hole has the effect of the one-way valve, the air can be allowed to pass while the passing of the flameis avoided. According to t