Abstract: The research on the Cretaceous climate and vegetation is fundamental to understand the formation of present environment. The palynological study of 11 samplles from Lower Cretaceous Liupanshan Group on the Sikouzi section(spanning 116-103 Ma),Liupanshan basin was carried out. 55 species(45 genera) of spore and pollen are detected. The palynoassemblages are diverse,with gymnosperms dominant and ferns abundant but angiosperms rare. the gymnosperms are predominated by Cheirolepidiaceae of Coniferales,and the ferns are dominant of Lygodiaceae and Schizaeaceae. The palynological data show that the Early Cretaceous floras are derived from various settings,i.e. the Coniferales plants on the high elevation mountain,the Cheirolepidiaceae plants along the low hill near the lake,the fern grow marsh wetland,and algae in the fresh water of the lake. The palynoflora indicates that the climate in the Liupanshan area is hot and dry ,and the palaeogeography is characterized by complex and various outlook during the late Early Cretaceous Furthermore,the climate evolution revealed by the vegetation can be divided into two stages in this time window. From 116 Ma to 112 Ma,the concentration of Cheirolepidiaceae and Schizaeaceae which developed in the environment of hot and dry are relatively low,and the concentration of conifers are significantly increased,as well as the concentration of ferns is not varied. All those indicate that the climate is humid and cold during this period. From 112 Ma to 103 Ma,the concentration of Cheirolepidiaceae and Schizaeaceae which developed in the environment of hot and dry are relatively high,and the concentration of conifers are significantly decreased. Compared to the upper stage,the total percentage of Lygodiaceae spores were relatively lower. the vegetation change during this period may indicate an increased trend of the dry and hot degree in this regionThe trend of climate change recorded by the pollen assemblages coincide with the global sea surface temperature fluctuation,thus indicates that the climate change recorded by the palynological assemblage in the Sikouzi section has the good response to the global climate change.

Key words: palynology, palaeoecology, palaeoclimate, early Cretaceous, Liupanshan Basin