Abstract: Definition of sequence stratigraphy on the offshore of Qingdao is carried out based on the analysis of microfossil properties of QDD3 core sediments and seismic data. Depositional system research is helpful to the spatial and space stratigraphy comparison using the conception of sequence. A half third-level se-quence, considering no obvious evidence of sea-level drop in the East China Sea region, can be classified, which is composed of Transgressive Systems Tract (TST) and Highstand Systems Tract (HST) on the study area. Transgression boundary formation is an important interface above riverbed sediment. Its li-thology is sandy coarse sediments and abundant with shell fragments. Microfossil abundance and diversity is at low-level. Lithology in condensed section is mainly mudy fine particle with worm holes, and abun-dance of microfossil gets its maximum value. Distinguishing of marine flooding surface from condensed sec-tion in the offshore region by seismic reflection feature is sometimes difficult as for the rapid depositional rate and multi-resources, so integrated utilization of lithology, microfossil and mineral character can be an effective method for recognizing the sequence stratigraphy.