Driving　style　is　a　comprehensive　representation　of　the　driver＇s　internal　psychological　factors　as　well　as　external　environmental　and　traffic　management　factors.　Identifying　driving　styles　can　help　suggest　targeted　management　strategies　and　personalized　active　safety　and　autonomous　driving　strategies.　This　paper　analyzes　the　drivers＇　driving　styles　according　to　the　vehicle　trajectory　data　from　unmanned　aerial　vehicle　(UAV)　videos.　Nine　characteristic　indexes　from　two　aspects　of　drivers　themselves　and　their　interaction　with　the　surrounding　vehicles　are　extracted.　The　principal　component　analysis　and　K-means　clustering　method　are　used　to　reduce　the　index　dimensionality　and　classify　the　driving　styles　of　merging　vehicles.　The　results　show　that　the　drivers＇　driving　styles　could　be　classified　into　four　categories:　aggressive,　relatively　aggressive,　relatively　cautious,　and　cautious.　The　analysis　of　the　characteristics　of　different　driving　styles　shows　that　it　is　feasible　to　classify　driving　styles　based　on　trajectory　data.