Electrical　capacitance　tomography　(ECT)　is　a　non-invasive　multiphase　flow　detecting　technique,　and　sensor　optimal　design　is　one　of　the　key　parts　in　ECT　technique.　The　senor　design　is　multi-parametric,　and　has　multiple　indicators.　Therefore,　the　orthogonal　design　is　introduced　to　deal　with　the　optimization　of　three　structural　parameters　of　the　sensor　plates　including　the　length,　the　central　angel　and　the　number.　A　combinatorial　fuzzy　index　of　ECT　(CFIECT)　is　defined　and　presented　as　a　multi-parametric　indicator　for　optimization　of　the　senor.　Meanwhile,　the　uniformity　index　Pcv　and　the　image　error　Ier　are　set　as　the　single　optimization　objective　respectively　to　compare　with　the　new　method,　CFIECT.　Experimental　results　indicate　that　the　sensor　structure　optimized　by　CFIECT　exhibits　a　greater　even　sensitivity　distribution　and　a　better　imaging　reconstruction　result　at　the　same　time,　which　provides　a　new　method　for　optimization　of　the　ECT　sensor　design.　©,　2014,　Science　Press.　All　right　reserved.