Abstract: On the basis of analyzing and testing ordinary inverting circuits,a new type inverting circuit has been put forward in this article.This kind of inverting circuit,with highly reliability and efficiency,has been named as "complex-isolated" inverting circuit.Moreover,a new kind of air plasma cutting power source with one of this complex-isolated invertor has also been developed.Non-HF igniting and a special output characteristics with a low starting curret are the main properties of the cutting power source,meanwhile,the design principle of the output controlling system has been dealed with in the article.The experimental results show that the cutting power source has highly reliability,highly efficiency,low disturbance,prefect cutting quality and easy-operating.The research and design of high power invertor in other fields will benefit from the complex-isolated inverting circuit which has been discussed in the article.