The utility model relates to a plasma cutting machine control device. The external collected signal partly enters into an A/D modular converter of digital signal controller after passing through a photoelectric coupler and lever translator and outputs accurate PWM wave, so as to ensure the stability of output current; and partly passes throught a logic comparator to compare and then enters into a digital signal controller to perform judgement, then the failture signal is output. A three-way selective switch, an air-pressure setting button and a current setting button signal enter into the digital signal controller and the output corresponding signal is displayed on a pneumatic indicator and current indicator. The device can increase power factor, reduce the interference of harmonic wave to electric network, the stability of the output direct current is high, therefore the cutting quality is increased.