Crop　residue　open　burning　has　substantial　negative　effects　on　air　quality,　human　health,　and　climate　change,　and　accurate　and　timely　estimates　of　its　air　pollutant　emissions　are　essential.　Open　burning　proportion　(OBP)　is　the　key　parameter　in　estimating　the　emission　from　the　crop　residue　open　burning　by　bottom-up　method.　However,　the　OBP　is　mainly　obtained　by　field　investigation,　which　consumes　much　time,　manpower　and　financial　resources,　leading　to　the　OBP　data　deficient　seriously.　In　this　study,　the　significant　logarithmic　relations　were　found　between　OBP　and　fire　radiative　energy　(FRE),　and　then　the　FRE-based　OBP　estimation　models　were　developed　for　different　regions　of　China.　The　comparison　between　the　FRE-based　OBP　and　the　field-investigated　OBP　illustrated　the　reliability　of　the　developed　models　(r　=　0.71,　NMB　=　-8%　and　NME　=　25%).　The　OBPs　of　different　municipalities/provinces　in　mainland　China　from　2003　to　2018　were　further　calculated.　The　results　showed　that　the　estimated　OBP　variation　exhibited　fluctuating　upward　trend　with　annual　mean　growth　rate　of　3.7%　from　2003　to　2014,　while　dramatically　decreased　with　annual　mean　reduction　rate　of　5.9%　from　2014　to　2018.　The　estimation　accuracy　of　emission　from　open　biomass　burning　can　also　be　can　be　significantly　improved　by　basing　on　the　yearspecific　OBP,　compared　with　the　calculation　based　on　fixed　OBP.　The　annual　PM2.5　emissions　would　decrease　4.5%-25.9%　and　increase　6.6%-30.7%　in　the　scenarios　of　a　fixed　OBP　during　2003-2014　and　2014-2018,　respectively.　The　developed　models　complemented　the　severely　missing　OBP　data　of　mainland　China　for　the　first　time.　By　combining　the　advantages　of　bottom-up　approach　and　FRE　method,　the　proposed　FRE-based　models　can　avoid　their　disadvantages,　and　can　help　to　get　more　accurately　and　timely　emissions　from　crop　residue　open　burning.