This　paper　introduces　a　plunger　limit　switch　testing　system　based　on　Virtual　Instrument　Technology　with　servo　control　module　and　data　acquisition　module.　The　proposed　system　is　designed　for　measuring　contact　resistance,　force-displacement　curve　and　voltage-displacement　curve.　And　the　product　qualification　is　automatically　judged　according　to　the　measured　result.　Field　experiment　shows　that　the　parameter　testing　system　has　a　stable　and　reliable　performance　with　high　precision.　©　(2014)　Trans　Tech　Publications,　Switzerland.