o　grasp　the　distribution　law　of　particulate　matter　at　an　intersection,by　collecting　the　concentrations　of　particulate　matter　at　many　intersections　in　Beijing　and　further　analyzing　the　correlation　between　particle　concentration　and　traffic　characteristics　and　fitting　estimation　of　data,　a　spatial　diffusion　model　of　particulates　at　the　intersection　was　established.　Finally,　the　distribution　of　particles　at　the　intersection　of　urban　roads　was　obtained.　Results　show　that　the　distribution　of　particulate　matter　on　the　cross　section　of　the　intersection　is　higher　in　the　center　and　then　decreases　to　the　two　sides.　The　higher　the　concentration　of　particulate　matter　at　the　point　near　the　intersection　parking　line　is,　the　greater　the　fluctuation　is.　The　fluctuation　of　the　particle　concentration　on　the　sidewalk　is　higher　than　that　on　the　driveway.　The　regularity　of　PM2.5　in　particulate　matter　is　consistent　with　that　of　PM10　in　particulate　matter.　©　2019,　Editorial　Department　of　Journal　of　Beijing　University　of　Technology.　All　right　reserved.