Based　on　the　efficiency　model　of　the　BUCK　PFC(Power　Factor　Correction)　LED(Light　Emitting　Diode)　driver　circuit,　the　theory　analysis　of　the　inductor　optimal　design　is　proposed　in　this　paper,　where　the　inductor　operates　in　BCM(Boundary　Conduction　Mode).　Considering　about　the　frequency　performance　and　EMI　(Electro　Magnetic　Interference)　of　the　driver　circuit,　the　boundary　condition　of　the　frequency　is　given　in　the　paper.　The　simulation　and　experiment　results　are　presented　to　verify　the　theory　analysis　of　the　inductor.　©　2011　IEEE.