Abstract: In allusion to a 660MW supercritical boiler after the transformation of low NOx swirl burner, through the variable conditions (different oxygen, different air distri-bution mode, the secondary air opening, the central air opening, different air swirl intensity of the tertiary air and the quartic air, etc.), the NOx emission characteristics and burner economy were measured.The test results showed that there are oxygen, the operation of air distribution of different layers burner and burner adjustment has certain in-fluence on the emission of NOx.The Operation suggestions were given:1) the oxygen should be controlled at about 2.3%, the environmental protection and economic of boiler could get balance; 2) the air distribution of different layers of burner should adopt as tower form, i.e.the upper burn-er throttle opening 40%, middle opening 60%, the lower opening 80%; 3) the burner adjustment should following this settings:the central air burner and secondary air holds a small opening, tertiary air vane angle of 30 degrees, quar-tic air vane angle of 45 degrees.

Key words: LNASB burner, low NOx Combustion, NOx emission, combustion regulation