The invention discloses a cyclone furnace. The cyclone furnace comprises a cyclone cylinder and a secondary combustion chamber, wherein a melting reaction tank is arranged below the cyclone cylinder and the secondary combustion chamber; a front-arranged chamber is arranged at the top of the cyclone cylinder, a raw material spray pipe used for spraying raw materials into the cyclone cylinder and afuel pipe used for introducing the fuel are arranged in the front-arranged chamber, the side wall of the cyclone cylinder is provided with an air supply port, wherein the air supply port is located below the raw material spray pipe, and the air supply port is tangent to the inner wall of the cylindrical combustion chamber of the cyclone cylinder; the bottom of the cyclone cylinder is provided witha first communication port used for enabling the salt in a molten state to flow into the melting reaction tank; and an exhaust channel is formed in the top of the secondary combustion chamber, a smoke discharge pipe used for enabling gas generated from the melting reaction tank to enter the secondary combustion chamber and a second communication port used for enabling the salt in the molten stateto flow into the melting reaction tank are arranged between the secondary combustion chamber and the melting reaction tank; and a bubbling device is arranged at the bottom of the melting reaction tank. The invention further discloses a salt-containing waste liquid combustion treatment method and a sodium sulfide preparation method.