The invention relates to an annular discharge based transient state plasma igniter. An insulation sleeve is located in an insulation protection sleeve, and one end of the insulation sleeve is located in a cathode. An anode conduction rod is located in the insulation sleeve, and one end of the anode conduction rod is arranged in a center hole of the cathode. One end of the insulation protection sleeve is arranged in a fixing base. The anode is located in the cathode. The transient state plasma igniter is provided with a mixed gas channel. According to the invention, high-energy nanosecond pulse is used to discharge electricity to form a local high temperature area, and a large quantity of active particles are activated to ignite combustible mixed gas in an extremely short period of time. The ignition area is large, and the mixed gas can be ignited by multiple points; the ignition time is extremely short, and the ignition delay time is shorter; the ignition energy can be well coupled with the gas mixture, macromolecule hydrocarbon fuel in the ignition area is ionized as active particles with low activation energy, so that the chemical reaction of the mixed gas is faster, the reaction time is shorter, and the ignition success rate is high.