In　order　to　investigate　NO　formation　during　the　preheating-combustion　process　of　pulverized　coal,　two　high-temperature　drop　tube　furnaces　were　connected　in　series　to　study　the　effect　of　preheating　temperature,　residence　time　and　air　equivalence　ratio　on　NO　formation.　Meanwhile,　The　NO　generation　simulation　and　ROP　(rate　of　production)　analysis　during　preheating-combustion　process　were　performed　by　means　of　Chemkin　Pro.　The　experimental　results　show　that　the　NO　yields　reduces　under　both　higher　preheating　temperature　and　longer　preheating　residence　time.　With　the　increase　of　the　air　equivalence　ratio　in　the　preheating　zone,　the　NO　yields　decreases　first　and　then　increases,　and　the　optimal　pre-combustion　zone　air　equivalence　ratio　is　obtained　around　0.4.　Reaction　kinetic　simulation　analysis　reveals　that　NH2,　CH3,　HCCO,　NCO　and　HCO　are　the　main　NO　reduction　chemical　groups　in　the　preheating-combustion　process　of　pulverized　coal,　but　the　reduction　of　NO　by　hydrocarbons　is　significantly　stronger　than　that　of　nitrogen-containing　compounds.　Meanwhile,　the　presence　of　O　radical　is　an　important　factor　in　NO　reduction.　©　2020　Chin.　Soc.　for　Elec.　Eng.