The Altai Mountain is situated in the heart of Asia on the state borders between China, Russia Federation, Mongolia, Kazakhstan and has good ecological environment and rich in plant resources.Based on consulting of specimen and filed investigation, the difference in species, composition and areal types of seed plants of China Xinjiang Altai Mountain, Russia Altai Mountain,Mongolia Altai Mountains and Kazakhstan Altai Mountains were compared and similarity of seed plants among four regions was analyzed.Results showed that:(1)The resources of wild seed plant are rich in the four Altai Mountain.Descending by the richness in turn:Russia Altai Mountains＞ Mongolia Altai Mountains＞ China Xinjiang Altai Mountains＞ Kazakhstan Altai Mountains.(2)Family and genus containing 1 and 2-10 species predominate at family and genus level in the four places.(3)The areal type of family of seed plants in four Altai Mountain is mainly Cosmopolitan and N.Temp.types, and at the genus level it is mainly N.Temp.Types.，Cosmopolitan， OW Temp.，Medit., W.As.to C.As.Types.(4) Similarity coefficient of seed flora in four Altai Mountain regions at family and genus levels is more than 50％, which meant the high similarity of seed plant flora between each other.It is suggested that there are difference in the four places of Altai Mountain.The Altai Mountain of China Xinjiang as a bridge for the all flora contacts, mix and serve.