Mesolithic site Ust’-Kova I was discovered in 1977 and investigated by Northern Angara archaeological expedition that was organized by Krasnoyarsk State Pedagogical Institute at the end of 1980. The article summarizes the research of Ust’-Kova I that were carried out in the framework of heritage preservation within construction area of Boguchany HPP from 2008 to 2011. There were distinguished three cultural horizons. The upper layer is a mix of archaeological material of different period: from Mesolithic to ethnographical modernity. The material of lower layer is the most interesting because it includes the Mesolithic material. Its attributes a developed technique that is based on microblades obtained from wedge – shaped, prismatic and edge-faceted microcores. There are angle burins, transversal and volumed many-faceted burin-drills, numerous of retouch microblades. The investigation of Ust’-Kova I from 2008 to 2011 had significantly expanded the information base about Mesolithic period of the Northern Angara region.