A DC solid power switch circuit includes a main power circuit, a subsidiary power circuit parallel to the load, an isolated drive protection circuit composed of a drive supply, a drive isolation circuit, a slow turned-on-off control circuit, a discriminating control circuit, a short circuit protection circuit and a push and pull output circuit, a current detection circuit, a voltage detection circuit, a main power valve drive circuit, a light-coupled isolating circuit, an assistant power valve switch-on logic circuit and a power drive output circuit, which can limit the current impulse in the period of switching on capacitive load, and suppress the peak voltage in turning off the inductive load.