VOCs　are　an　important　precursor　pollutant　of　ozone　(O3)　and　secondary　organic　aerosols　(SOA).　Vehicle　evaporative　emission　is　an　essential　source　of　VOCs　in　urban　area,　among　which　lack　of　localized　tests　of　running　loss　process　in　China.　This　study　tested　all　the　evaporative　emission　processes　of　in-use　light-duty　gasoline　vehicles　(LDGVs),　including　refueling,　running　loss,　hot　soak,　and　48-h　diurnal　breathing　loss　(DBL)　based　on　the　variable　temperature　Sealed　Housing　for　Evaporative　Determination　(VT-SHED)　of　REU　(China　4,　China　5)　vehicles　and　REC　(China　6,　with　Onboard　Refueling　Vapor　Recovery　system)　vehicles.　The　emission　factors　(EFs),　species　profiles,　Ozone　formation　potential　(OFP),　and　SOA　formation　potential　(SOAP)　of　all　evaporative　emission　processes　of　REU　and　REC　vehicles　were　obtained.　We　found　that　the　running　loss　emissions　was　less　affected　by　the　Onboard　Refueling　Vapor　Recovery　(ORVR)　system,　the　average　running　loss　EFs　of　REU　and　REC　vehicles　was　9.386　mg/km;　refueling　and　DBL　EFs　of　REC　vehicles　was　1.491　mg/L　and　0.179　g/day,　respectively,　99.8%　and　56.0%　lower　than　those　of　REU　vehicles,　the　hot　soak　EFs　was　0.087　g/h　in　average.　The　refueling　emissions　process　was　dominated　by　alkanes　(REU:　77.8%;　REC:　75.4%),　and　C4　and　C5　species　dominated　(REU:　75.6%;　REC:　67.6%).　Among　the　running　loss,　hot　soak　and　DBL　emissions,　alkanes,　oxygenated　VOCs　(OVOCs)　and　aromatics　were　the　dominant　VOCs　groups,　OVOCs　account　for　a　higher　proportion　in　REC　vehicles　than　in　REU　vehicles.　REC　vehicles　had　higher　proportion　of　C1-C3　than　REU　vehicles,　it　may　be　that　ORVR　has　a　better　adsorption　effect　on　species　with　large　carbon　numbers.　Running　loss　VOCs　species　had　a　strong　correlation　with　hot　soak　VOCs　species.　The　OFP　of　running　loss　in　REU　and　REC　vehicles　were　0.9-1.3　and　0.3-0.7　times　higher　than　those　of　refueling　and　48-h　DBL,　while　the　SOAP　were　10.7-12.9　and　both　1.1　times　higher,　respectively.　These　findings　can　provide　valuable　basis　for　emission　estimation　and　characteristic　analysis　for　evaporative　process　of　LDGVs　and　support　the　development　of　appropriate　pollution-control　policy.