The invention belongs to the technical field of plasma combustors capable of being used for the petrochemical industry, the metallurgy industry, the electric power industry and the like, and particularly relates to a double-medium fuel gas source plasma combustor. The combustor comprises at least two cathode passageway pipes, an air pipe, a fuel gas pipe, a burner sleeve, cathodes, anodes and insulating layers. One of the air pipe and the fuel gas pipe is arranged around the outer walls of the at least two cathode passageway pipes. Each cathode is installed at one end of the corresponding cathode passageway pipe. The anodes are installed at one end of the air pipe and one end of the fuel gas pipe correspondingly. Each anode and the correspondingly cathode appear as a set. In this way, double fuel gas sources including fuel gas and air are used as medium gas sources for generating thermal plasmas, the partial unionized fuel gas and the air are combusted, and required temperatures can beobtained on the two aspects of fuel chemical heat and the plasmas; and meanwhile, combustion of electric energy of the plasmas is reduced, ignition devices are omitted, the flame temperature is higher, and poor-quality coal gas extremely low in heat value can be combusted.