Provided is a fuel cell hybrid system. The fuel cell hybrid system includes a heat engine including a compression unit for compressing an oxidizer supply gas including air and an expansion unit for expanding the oxidizer supply gas to generate mechanical energy, a fuel cell including an anode for receiving a fuel gas, a cathode for receiving the oxidizer supply gas, and a catalytic combustor for burning a non-reaction fuel gas of an anode exhaust gas exhausted from the anode to heat the oxidizer supply gas, a first heat exchanger heat-exchanging the oxidizer supply gas discharged from the compression unit with a cathode exhaust gas exhausted from the cathode, and a second heat exchanger heat-exchanging the oxidizer supply gas discharged from the first heat exchanger with the oxidizer supply gas discharged from the catalytic combustor. The oxidizer supply gas discharged from the second heat exchanger is supplied into the catalytic combustor via the expansion unit, and the oxidizer supply gas discharged from the catalytic combustor is supplied into the cathode via the second heat exchanger.