The flora of ‘Shushensky Bor’ National Park as a result of the research was supplemented with species: Selaginella sajanensis, Asplenium trichomanes, Woodsia taigischensis, Circaea caulescens, Orobanche krylowii, Schisandra sinensis, Athyrium monomachii, Cystopteris sudetica, Cirsium komarovi, Stellaria zolotuchini, Archangelica sajanensis, Botrychium virginianum, Ostericum palustre, Epipactis palustris, Epipactis helleborine, Persicaria hydropiper. Three species are described as new: Rhododendron sajanense, Saussurea schweingruberi, Allium nebularum. New Rhododendron is a high semi-evergreen shrub up to 4.5 m height , at the base of trunks up to 9 cm in diameter. This species is related with humid re-gions of the Sayan Mountains and mountain taiga belt, and spread down slopes to the Yenisei river. Similar plants are found in the Eastern Sayan on the Kazyr river in Kuraginsky district of Krasnoyarsk Region. This species is more mesophilic among close relatives and has features in anatomy leaf lamina: upper side less pubescence, cells of abaxial epidermis are thin-walled; air areas in the mesophyll are small. Most closely related species is R.sichotense occuring in the Far East region. Saussurea schweingruberi is closely related with S.parviflora and S.stolbensis, from which differs by rough leathery leaves, has a caudex and occurs in rocky habitats in subalpine and mountain taiga zones. The species is also observed in the ‘Ergaki’natural park. New onion (Allium nebularum) is most similar to A.tytthocephalum, from which differs by chromosome number (diploid), habitus, features of flowers. The species is related with rocky scree and rocky banks of streams exclusively in mountainous areas of the Western Sayan. It also occurs in the ‘Sayano-Shushensky’ Reserve. The total diversity of vascular plants in the National Park is 856 species.