Detailed analysis of planktonic foraminifers was performed at bore hole DF1-111, hemas-microsoft-com:office:smarttags" />Yinggehai Basin. A comparison with the stratigraphic sequence from ODP Leg 184 and with the international standard chronostratigraphic timescale published in 2008, the planktonic foraminiferal biostratigraphy and chronostratigraphy of DF1-1-11 were set up. Quantitative analysis of foraminifers provides important information about environmental variations at the bore hole. The evolution of sedimentary environments at the bore hole is also discussed in detail based on the statistics of foraminiferal abundance, diversity, percentage of planktonic foraminiferal, and assemblage characteristics. This study will be beneficial for future researches on the biostratigraphy and chronostratigraphy of the Yinggehai Basin and its adjacent areas.