A solid-state high voltage switch for pulsed gas laser based on magnetic pulse compression system was developed in the experiment. The output efficiency of the magnetic compression switch was maximized by adjusting the reset current and load resistance. After being compressed by two-stage magnetic switch, the pulse width was about 5% of the original. The rising time after compression was about 180 ns, and the amplitude was about 16 kV. The first-stage magnetic compression efficiency was 89.2%, the second-stage magnetic compression efficiency was 97.7%, and the total compression efficiency reached 87.2%. After receiving the laser, the measured output laser pulse energy was about 20 mJ, the output laser pulse half-height and width were about 85 ns.