The invention relates to a combustion method and device for preventing combustion coking and contamination of high-sodium coal. An outlet of a fluidized bed is connected with an inlet of a cyclone separator, one outlet of the cyclone separator is connected with one inlet of a coal mill through a heat exchanger and a dust remover, the other outlet of the cyclone separator is connected with one inlet of a coke preprocessing device, an outlet of the coal mill is connected with the other inlet of the coke preprocessing device through a three-grade pyrolysis bed, an outlet of the coke preprocessing device is connected with an inlet of a turbulent burner on the fluidized bed, and a forced draught fan is respectively connected with a primary air inlet in the bottom of the fluidized bed and a secondary air inlet in the middle of the fluidized bed. According to the combustion method and device, a common pyrolysis device is replaced by the three-stage fluidized bed, pyrolysis gas sodium-removal purification devices are connected behind the three stages of the three-grade pyrolysis bed respectively, the problem that alkali metal sodium elements are transformed between forms in the pyrolysis process and can not be effectively removed can be effectively solved, the problem that coke can not be easily and effectively combusted in a common pulverized coal furnace can be well solved, and energy can be effectively used.