PCA　algorithm　and　MLR　model　are　used　to　figure　out　the　route　and　degree　that　heavy　duty　trucks　pollution　has　contributed　to　the　severe　air　pollution　weather　in　Beijing　from　2002　to　2016.The　variance　contribution　rates　of　DHDT,DPM,DNO　and　DGTKM　exceed　50%　by　variance　analysis,which　indicates　that　the　trans　provincial　freight　turnover　demand　is　the　key　factor　causing　the　increase　of　the　number　and　mileage　of　heavy-duty　trucks,and　in　turn　causing　a　large　amount　of　diesel　consumption　and　significantly　increasing　the　concentration　of　NO2　PM10　and　PM2.5　in　Beijing.The　number　of　heavy-duty　trucks,trans　provincial　cargo　turnover　and　NO2　concentration　are　significantly　correlated　with　PM10　and　PM2.5　concentration.Each　standard　unit　increase　in　FAC,CO　concentration　and　diesel　consumption　of　heavy-duty　trucks　will　increase　the　days　of　heavy　air　pollution　in　Beijing　by　1.489　standard　units.Therefore,among　the　pollution　factors　concerning　heavy-duty　trucks,the　number　of　heavy-duty　trucks,trans-provincial　freight　turnover　and　diesel　consumption　are　the　main　causes　for　the　increase　of　servere　air　pollution　days　in　Beijing.The　generation　and　emission　of　NO2,PM10,PM2.5　and　CO　are　the　main　pollution　paths.　©　2019,　China　National　Chemical　Information　Center.　All　right　reserved.