A　new　instrument　is　developed　to　detect　hemodynamic　parameters,　which　needs　not　measure　blood　pressure　beforehand　and　therefore　more　convenient.　Integrated　with　a　blood　pressure　measuring　module,　this　system　can　measure　blood　pressure　value　automatically.　The　signal　of　pulse　wave　can　be　detected　by　a　pulse　pressure　sensor,　amplified　and　filtered,　and　finally　transferred　into　digital　signal　used　in　PC　by　means　of　an　A/D　converter.　Making　use　of　double　elastic　cavities　module,　the　software　of　this　system　can　work　out　hemodynamic　parameters　such　as　heart　rate,　coefficient　of　pulse　wave,　and　so　on　based　on　basic　information　of　patient　including　blood　pressure　value.　Demonstrated　by　comparison　experiment　and　repeatability　experiment,　this　system　possesses　high　accuracy　and　good　repeatability　and　thus　can　be　applied　to　clinic　and　family　health　care.