Two Rhododenderon chromene meroterpenoids,isoconfluentin (1) and (+)-confluentin (2),were isolated from the petroleum ether extract of ethanol fraction of the leaves of Rhododendron rubiginosum Franch.var. rubiginosum by using various chromatographic methods,including MCI Gel,sephadex LH-20,ODS,silica gel and semi-preparative HPLC.Their planar structures were identified by spectrographic methods,such as NMR,UV,IR,MS,and the absolute configuration of C-2 of 1 and 2 was determined to be the S configuration by the chromane/chromene helicity rule.Compound 1 is a new compound,and compounds 1 and 2 showed effective anticoagulant effect via prothrombin time assays in vitro.