According　to　the　principle　of　software　radio　technology..　and　combining　with　the　hardware　architecture　and　the　main　feature　of　programming　of　the　high　performance　floating-point　Digital　Signal　Processor　TigerSHRAC,　this　paper　mainly　does　the　research　of　automatic　recognition　arithmetic　for　the　modulated　signal　which　is　from　the　digital　receiver　to　recognize　which　modulating　method　it　adopts.　In　this　paper,　the　optimizing　method　is　introduced.　And　also　the　program　flow　chart　and　the　running　results　of　the　signal　recognition　program　are　given　here.