Coplanar　capacitive　sensors　have　been　widely　applied　in　many　fields　with　its　characterstics　of　non-invasion,　lowcost　and　fast　response.　A　complex　structure　of　coplanar　capacitive　sensor　is　designed　to　be　used　for　the　film　thickness　measurement.　Firstly,　three　types　of　coplanar　capacitive　sensors　with　different　shapes　are　designed,　and　according　to　the　experimental　reuslts,　the　parameters　affecting　the　sensor　signal　strength　and　sensitivities　are　discussed,　the　electric　field　distributions　of　sensors　are　simulated　by　COMSOL.Then　the　fringe　capacitance　of　a　series　of　spiral-type　sensors　are　measured　and　analyzed.　The　experimental　results　indicate　the　rational　geometrical　parameter　design　about　the　coplanar　capacitive　sensor　can　improve　the　sensor　performance　obviously.　©　(2014)　Trans　Tech　Publications,　Switzerland.