The utility model discloses a combustion device for starting alcohol-based fuel vaporization combustion and realizing strong fire by natural gas. The device comprises an alcohol-based fuel storage tank, an alcohol-based fuel input pipe, an oil inlet electromagnetic valve, a combustion controller, a fuel pump, an ignition wire, a vaporization pipeline inlet, an ignition needle, a vaporization pipeline, a natural gas nozzle, a vaporization furnace end, an alcohol-based fuel nozzle, a vaporization pipeline outlet, an alcohol-based fuel output pipe, a natural gas electromagnetic valve, a natural gas input pipe, an air chamber, an air inlet and an air blower. In the starting and working process of the device, only natural gas is combusted to provide firepower, the device can be used immediatelyafter being opened, after the device works for a period of time, alcohol-based fuel enters the vaporization pipeline and is rapidly vaporized, gaseous alcohol-based fuel is sufficiently combusted innatural gas flame after being sprayed out, and the problem that eyes are pungent in the starting process is solved; under a special working condition, the working requirement of strong fire can be metby opening and increasing the input of natural gas; and in the working finishing process, the problem that eyes are pungent due to residual alcohol-based fuel does not occur.