A　kind　of　heart　rate　variability　detector　based　on　embedded　system　is　researched,　which　gets　the　heart　rate　parameters　with　the　photoelectric　volume　pulse　and　works　out　heart　rate　variability　conveniently　and　noninvasively　in　real-time.　The　detector　obtains　volume　pulse　wave　through　the　sensor　of　photoelectric　volume　pulse　wave　and　sends　it　to　the　Amplification　circuit,　filter　circuit,　and　A/D　conversion　and　then　into　real-time　microprocessor.　In　the　microprocessor,　signal　is　processed　and　parameters　are　obtained.