Investigation data from sampling plots in field were used to study the floristic origin and species diversity in east of Qinghai lake. The results are as follows：①The species of sandy vegetation are simple, there are 71 species, belonging to 58 genera in 27 families, with the highest proportion families Gramineae, accounting for 22.535%; second Compositae, for 12.676%; third Legume, for 9.8592%; the least Campanulaceae, et al 14 families, only for 1.4085%. ②In flora, the distribution\|type of family of the sandy vegetation in east of Qinghai lake mainly belong to widespresa type, 16 families, having a percentage of 83.1%, and the dominant families of lake area are all of widespresa type; the sandy vegetation secondly belong to the temperate type, 10 families; the tropic type is simple, only 1 family. ③On the life form, Hemicrytophytes and Cryptrphytes are the main，which add to 76.06%, Chamaephyte and Phaenerophyte in the next place, Therophyte is the least. ④The sandy vegetation association in east of the Qinghai Lake is mostly composed by single dominant species. The changing tendency for species diversity index H , richness index R1，and evenness index Jsw show almost the same increasing trend with species increasing; the changing tendency of the ecological dominance is just on the contrary. ⑤The species similarity of sandy vegetation association change largely, between 0.1132 and 0.5567. The species similarity of fixed dune association is higher, but that of semi\|moving and moving dunes are lower.