This　study　aimed　to　establish　the　emission　factors　and　the　emission　inventory　of　agricultural　machinery　in　Beijing　in　2017　under　real-world　operation.　The　emissions　of　typical　harvesters,　tractors,　agricultural　transport　vehicles,　and　farm　construction　machinery　under　real-world　operation　were　tested　by　a　portable　emission　measurement　system.　The　results　showed　that　different　operation　modes　have　a　greater　impact　on　the　tailpipe　emissions　of　agricultural　machinery.　The　CO,　NOx,　HC,　and　PM　emissions　were　relatively　stable　when　the　engine　is　idling　and　moving　compared　to　when　the　excavator　is　performing　actual　work.　According　to　the　classification　and　emission　standards　of　various　types　of　machinery,　a　relatively　perfect　emission　factor　system　of　agricultural　machinery　in　Beijing　was　established,　which　can　provide　reference　and　support　for　relevant　research　and　management　decisions.　According　to　the　emission　factors　of　agricultural　machinery　and　fuel　consumption　in　Beijing,　the　emissions　of　CO,　NOx,　HC,　and　PM　in　2017　were　2　566.60,　1　239.29,　563.08,　and　538.32　t,　respectively.　The　total　pollutants　of　transport　machinery,　tractors,　and　combined　harvester　accounted　for　98%,　95%,　95%,　and　98%　of　the　total　concentrations　of　CO,　NOx,　HC,　and　PM,　respectively.　Therefore,　transport　machinery,　tractor,　and　combined　harvester　should　be　the　key　control　objects　in　the　reduction　of　agricultural　machinery　pollution.　©　2020,　Science　Press.　All　right　reserved.