This　study　investigates　the　potential　sources　and　transport　pathways　of　PM2.5　in　Shanghai,　China　from　January　2013　to　December　2014　by　using　the　Hybrid　Single-Particle　Lagrangian　Integrated　Trajectory　(HYSPLIT)　modeling,　K-means　clustering,　and　concentration-weighted　trajectory　(CWT)　analysis　methods.　Six　transportation　pathways　that　contribute　to　PM2.5　in　Shanghai　were　identified　by　trajectory　clustering.　The　primary　potential　pathway　originated　from　the　nearby　northwestern　regions,　including　Hebei,　Henan,　Shandong,　Jiangsu,　and　Anhui,　which　mainly　affect　PM2.5　in　winter　and　spring.　The　second　primary　potential　pathway　originated　from　northern　and　north-western　regions,　such　as　Mongolia.　The　lowest　PM2.5　concentrations　were　found　in　the　southern　pathway　with　clean　marine　air　masses　from　the　South　China　Sea　and　Pacific　Ocean　in　summer.　The　CWT　method　also　identified　the　primary　potential　sources　on　the　basis　of　the　trajectory　clustering　results.