The invention belongs to the field of pulverized 
coal combustion and emission 
performance control, and particularly discloses a flameless graded 
oxygen-enriched low-
NOx combustion method and 
system. The method comprises the following steps that 
smoke participating in circulation is divided into three paths, the fuel with the preset 
mass carried by a primary air pipeline, a secondary air pipeline and a 
tertiary air pipeline is introduced into a 
hearth through the primary air pipeline, the secondary air pipeline and the 
tertiary air pipeline to be combusted, wherein air outlets of the primary air pipeline and the secondary air pipeline are positioned in a main 
combustion area and an air outlet of the 
tertiary air pipeline is located in a re-combustion area, and the injection amounts and themass flows of 
oxygen in air in the air pipelines are controlled so as to control the 
peroxide coefficient range and the flow characteristic of the main combustion area and the re-combustion area so that a fuel staged 
oxygen-enriched combustion mode, a fuel-oxygen two-way staged oxygen-enriched combustion mode and a flameless oxygen-enriched combustion mode are achieved. The 
system comprises a boiler, a 
flue gas pretreatment module, a 
chimney, the primary air pipeline, the secondary air pipeline and the tertiary air pipeline. According to the invention, stable and efficient low 
NOx emission canbe achieved, the ignition characteristic of pulverized 
coal can be improved, and pulverized 
coal reburning is promoted.