Abstract: From 30ka.B.P. to 20 Ka.B.P.,in the warm period before the fullglacial,lacustrinedeposit was formed in the Bihenying basin, in Qinglong county south-west Guizhouprovince. Mixed deciduous broadleaf and coniferous forests were growing on the hilly land,with a small varying between deciduous broadleaf forest and mixed coniferous and deciduousbroadleaf forest. The annual mean tempretrure was 1-6℃ lower than that of today.From 30 Ka.B.P to 26 Ka.B.P.,there were mixed deciduous broadleaf and coniferoustrees with a high proportion of Fagus and a tempreture 2-6℃ lower,Around 23 Ka.B.P.,deciduous and evergreen trees were mixed up, and annual mean tempreture was 1-3℃ lower than that of today.From 26 Ka.B.P. to 23 Ka.B.P.,and after 23 Ka.B.P,deciduousbroadleaf and comiferous three were mixed there. After that peiod climate turned to be dryand cold, pteridophyte grew widely. In the fullglacial period lacustrine deposition stopped,and was replaced by the chaotic sediments of muds and gravels.

Key words: Bihenying, Late guaternary system, Paleoenvironment, Pollen and spore