The invention discloses a high-voltage direct-current gas breaker based on a self-excited oscillation circuit. By the gas breaker, fault current can be cut off under high nominal voltage classes. The gas breaker comprises a superconducting current limiter and a cut-off module which are in serial connection. The cut-off module comprises gas breaker bodies in parallel connection, a current conversion circuit formed by serial connection of a capacitor and an inductance, and a non-linear resistor oxidation energy absorbing device. The fault current passes the superconducting current limiter first, is limited by the same, and is cut off by the gas breaker bodies. The gas breakers extinguish arc by using self exciting to generate artificial zero crossing points. The high-voltage direct-current gas breaker is fast in response, low in current overload coefficient, simple in structure, low in size, low in overvoltage, safe and reliable, short-circuit current does not exceed current quench of the superconducting current limiter, and other devices can be protected.