Abstract: The characteristics of sporopollen assemblage and climate evolution of Guantao Formation in eastern Bohai Bay area are obtained through drawing of the sporopollen spectrum and statistic analysis of sporopollen data, which are shown as follows. The evolution of tree layer is divided into two stages:coniferous tree-dominated mixed forest in the early Guantao Formation (with sporopollen assemblage zone Ⅲ and Ⅳ), and deciduous forest containing many subtropical elements in the late Guantao Formation (with sporopollen assemblage zone Ⅰ and Ⅱ). It is found from the statistics that the hygrophyte are significantly more than the xerophyte, and the philotherm more than the thermophile, with a typical subtropical monsoon climate characteristics. The S/A and E-T parameters are calculated by selected typical sporopollen to describe the climate changes between sample spots in detail, which proves that the climate of Guantao Formation fluctuated frequently and was mainly hot and humid.