Abstract: This paper systematically collects and integrates palaeotologic information from downhole Sangonghe formation and outcrops in lunggar basin, and pays mainly attention to study of the distribution of sporopollen assemblage of Classopollis high-content zone in Sangonghe formation. The results show that strata with Classopollis high-content zone are big in thickness and high in content in the foreland of North Tianshan mountain, and become thinning and reducing from the south to the north of Iunggar basin. The Classopollis high-content zone in top of lower member of Sangonghe formation in Junggar basin is correlated with Sangonghe formation of Meiyaogou section in Turpan-Hami basin, upper member of Yangxia formation of Kuqa river section in Tarim basin, No.2 and 3 members of Dameigou formation of Dameigou section in Qinghai region, upper part of Tandonggou formation in Minhe basin and Fuxian formation in southern Shaanxi-Gansu-Ningxia basin, reflecting an arid climate occurred in period of Toar- cian in the world. The Classopollis high-content zone is a good marker bed, and can be used as one of markers for distinguishing between Middle Jurassic and the Lower Jurassic in Junggar basin.

Key words: Junggare basin, Early Jurassic, Middle Jurassic, sporopollen assemblage