This　paper　investigated　the　characteristics　and　sources　of　organic　carbon　(OC)　and　elemental　carbon　(EC)　in　PM2.5　during　the　heating　season　in　Beijing.　PM2.5　samples　were　collected　at　the　Beijing　Normal　University　sample　site　during　the　period　of　December　2011　to　February　2012.　This　study　also　analyzed　the　concentrations　characteristics　of　PM2.5,　OC　and　EC,　calculated　the　concentrations　of　the　secondary　organic　carbon　(SOC)　based　on　the　minimum　ρ(OC)/ρ(EC)　ratio　method.　Besides,　the　sources　and　source　contributions　of　OC　and　EC　were　analyzed　qualitatively　and　quantitatively.　Results　showed　that　the　average　concentration　of　PM2.5　was　(90.69±61.86)　μg/m3,　the　average　concentration　of　OC　and　EC　were　(21.91±12.02),　(5.03±2.58)　μg/m3,　accounting　for　24.16%　and　5.55%　of　PM2.5,　respectively.　The　average　concentration　of　SOC　was　(8.37±6.05)　μg/m3,　accounting　for　37.27%　of　the　total　organic　carbon　(TOC).　The　high　correlation　coefficient　of　OC　and　EC　showed　that　the　source　for　OC　and　EC　was　the　same,　mainly　from　the　vehicle　emission,　the　coal　combustion.　The　vehicle　emission　was　the　major　source,　with　a　contribution　of　44.70%　to　the　OC　and　EC.　As　a　consequence,　controlling　the　number　and　reducing　the　emissions　of　motor　vehicles　have　become　an　important　measure　to　improve　the　atmospheric　environment　quality　in　urban　areas.