The invention relates to an efficient non-transfer arc plasma combustion system and method. The system comprises a combustion chamber, waste gas conversion valves and at least two non-transfer arc plasma systems, one end of each non-transfer arc plasma system extends into the combustion chamber, and the non-transfer arc plasma systems can generate plasma arcs in the combustion chamber and are the same in structure; and the non-transfer arc plasma systems are all communicated with the combustion chamber through the waste gas conversion valves. The method is achieved through the above system. By means of the system and method, effective use of energy cycle is achieved, and consumption of electric energy is effectively reduced. Waste gas conversion is carried out every a certain period of time, and the service life of a non-transfer arc plasma gun electrode is effectively prolonged.