This paper analyzes phytoliths assemblages from 70 topsoil samples collected at an altitudinal interval of about 50 m between 1 200 m and 4 600 m a.s.l. on the east slope of Gongga Mountains. Phytolith grains were carefully separated from soils and concentrated, accomplished by heavy-liquid flotation, then identified (28 types) and counted under microscope (at least 300 grains per sample). The results show that the topsoil phytolith assemblages can differentiate the altitudinal vegetation belts: 1)in mountainous subtropical evergreen broad-leaf forest belt, at 1 200～2 200 m a.s.l., the phytolith assemblages are mainly comprised of broad-leaf-type (6.8％), dumbbell (24.1％), cross (5.7％ )and short-saddle types; 2)phytolith assemblages from warm temperate mixed needle-leaf and broad-leaf forest belt, at 2 200～3 200 m a.s.l., are characterized by abundant broad-leaf-type, conifer-type, square, fan and long-saddle types. Broad-leaf-type decreased (2.3％) and conifer-type increased(2.1％). And Stipa-dumbbell appeared; 3)phytolith assemblages from cold temperate dark coniferous forest belt, at 3 200～3 700 m a.s.l., have abundant conifer-type (4.5％), rondel, trapezoid, point and Stipa-dumbbell types. Percentage of broad-leaf-type (0.6％) reduced dramatically; and 4)in subalpine shrub and meadow belt at 3 700～4 600 m a.s.l., the phytolith assemblages are mainly composed of rondel, trapezoid, gobbet and Stipa-dumbbell types.
