A　new　structure　of　capacitive　sensor　used　for　an　automatic　car-wiper　system　is　presented.　It　aims　to　develop　a　low-cost　sensor　with　high　sensitivity　and　robustness.　The　working　principles　of　the　sensors　used　for　liquid　on　the　surface　detection　are　introduced.　Three　types　of　proximity　capacitive　sensors　of　different　shapes　are　designed　under　the　same　outer　diameter.　The　parameters　affecting　the　sensor　signal　strength　and　measurement　sensitivity　are　discussed　based　on　the　performance　analyzing　of　the　sensors.　The　electric　field　distributions　of　the　sensors　are　simulated　and　the　fringe　capacitance　of　the　sensors　is　measured　and　analyzed.　For　the　flower-shaped　sensor,　the　noise　analysis　is　presented　and　the　measurement　results　are　given.　The　effects　of　the　excitation＇s　frequency　are　experimented　and　the　optimum　frequency　of　the　excitation　is　determined.　The　experimental　results　indicate　the　validity　and　importance　of　the　capacitive　sensing　technique　which　can　be　used　for　liquid　detection　on　windshield　of　vehicles,　and　the　new　structure　of　the　sensor　has　greater　measurement　performance,　especially　in　signal　strength　and　the　sensitivity.　©　2011　ISSN　2185-2766.