Themicroscopicmechanismoflowlevellaserirradiation(LLLI)mendingrheologyforbloodisanalyzedbythequantumtheory.Theresultsshowthatthelasercanresolvethefibrinclot,sothepropertyofbloodrheologyisimproved,andsomebondsofthecholesterolinbloodarefracturedbythelowlevellaser(LLL).Hencetheratioofmembranecholesteroltomembranephosphatideoftheredcellisreduced,andthenthebloodcirculationcanbeimproved.Theclinicalcuredtestsandsomecorrelativetestdatacanbeexplainedbythetheoreticalanalysesinthispaper.