The affecting regularity of first-stage pulverized coal（PC） concentration in multi-stage oil-less ignition technology has been studied. The first-stage PC Concentration affects directly the first-stage outlet flue gas temperature and combustibe gas content in the flue gas

but the first-stage outlet flue gas temperature is a deciding factor for the ignition of second-stage PC. Meanwhile

the combustible gas content in the first-stage outlet flue gas is helpful to the ignition of second-stage PC. Hence

the influence of first-stage PC concentration upon first-stage combustion has a very important effect in multi-stage ignition.