Non-methane　hydrocarbons　(NMHCs)　plays　an　important　role　in　haze　events.　This　study　focused　on　NMHCs　characteristics,　effects　on　secondary　organic　aerosol　(SOA)　and　source　apportionment　in　Handan　in　heavily　polluted　seasons,　i.e.,　autumn　(October　2017)　and　winter　(January　2018)　and　their　differences　in　non-haze　and　haze　days.　An　online　instrument　(AMA　GC5000)　was　used　to　monitor　NMHCs　in　Handan　firstly　at　the　campus　of　Hebei　University　of　Engineering.　It　was　found　that　the　average　NMHCs　concentrations　were　41.45　and　57.56　ppb　in　autumn　and　winter,　respectively,　which　were　higher　than　most　investigated　domestic　and　foreign　megacities　to　the　best　of　our　knowledge.　Alkanes　was　the　largest　contributor　to　NMHCs　(45.4%),　and　followed　by　alkenes,　aromatics,　and　acetylene.　In　haze　days,　the　concentrations　of　NMHCs　and　four　categories　increased　far　more　in　winter　than　those　in　autumn　compared　to　non-haze　days.　The　total　SOA　potential　(SOAP)　in　winter　(3364　mu　g　m(-3))　was　higher　than　that　in　autumn　(2804　mu　g　m(-3)).　The　total　SOAP　was　close　in　haze　and　non-haze　days　in　autumn,　while　it　was　much　higher　in　haze　days　in　winter.　Regardless　of　the　variations　of　different　periods,　aromatics　contributed　most　to　the　total　SOAP,　with　contributions　of　87　-　95%,　where　toluene　was　the　most　contributed　species.　Combined　the　results　of　diagnostic　ratios　with　positive　matrix　factorization　(PMF)　model,　NMHCs　of　Handan　was　mainly　contributed　by　traffic　emissions　and　combustion　events.　Vehicle　related　(from　23.2　to　30.1%)　and　industrial　related　source　(from　13.7　to　26.7%)　may　be　major　contributors　to　the　haze　pollution　in　autumn　and　winter,　respectively.