The invention discloses a 
metal surface 
combustor and a gas premixing method thereof, solves the technical problem that the 
combustor can uniformly mix gas with 
combustion air in a shorter premixing channel, and belongs to the technical field of 
combustion of 
metal surface combustors. The 
metal surface 
combustor is characterized in that a metal 
throat is a 
cylindrical channel; the outer side surface is connected with a boiler front wall; one part extending into a 
hearth is an end-sealed microhole 
metal cylinder; the other end is connected with an air 
pipe as a whole; multiple gas spray guns and multiple 
cyclone blades are arranged at the 
tail end of the gas 
pipe in sequence; the gas uniformly enters the 
throat by spray holes in the gas spray guns and gas 
pipe holes in the gas pipes; meanwhile, the 
combustion air and the gas are hedged and uniformly mixed in the 
throat; and under stirring of the 
cyclone blades at the end part of the gas pipe, the uniform mixing is further accelerated, so that the mixing distance is shortened, the 
flame temperature nonuniformity caused by nonuniform 
gas mixing is effectively prevented, and the 
NOx emission is reduced.