The invention belongs to the technical field of combustion of low-concentration premixed gas, relates to an accumulated ceramic ball porous medium burner and an application method thereof, and uses premixed gas with a concentration lower than the lower limit of explosion limit as a fuel. The accumulated ceramic ball porous medium burner is provided with a steady flow section shell, an insulation material, a combustion section shell, a combustion chamber, a heat insulation burnout chamber and a nozzle cavity; the combustion chamber at the front end in the combustion section shell is filled with a stopper brick and an accumulated ceramic ball porous medium; the low-concentration premixed gas is preheated in the accumulated ceramic ball porous medium, and is began to burn; the heat insulation burnout chamber is at the middle part in the combustion section shell for providing a full reaction space for the low-concentration premixed gas not totally burnt yet; the nozzle cavity is formed in the back part of the combustion section shell; and totally burnt smoke forms high-speed flows through the nozzle cavity for spraying to improve the heating efficiency of a heated workpiece. The accumulated ceramic ball porous medium burner is suitable for the low-concentration premixed gas with more impurities or dust; the porous medium material is long in service life; and the burner is easy to be installed and maintained.