Abstract: Seven gravity sediment cores were collected from muddy area of inner continental shelf of the East China Sea. Measurement of ²¹⁰Pb activity was performed on all cores. The results demonstrate that the sedimentation rates were between 0.79 and 3.66 cm/a, with 1.97 cm/a on average. The highest sedimentation rate was recognized in core CJ12-11, located in the high sedimentation rate area of East China Sea. Six other cores with relative low sedimentation rates were located in the sub-higher sedimentation rate area. Distribution of ²¹⁰Pb activity in surface sediments is correlated closely with the types of sediments, and probably controlled by the clay mineral, but shows a positive correlation with suspended matter concentration. Furthermore, these results reveal relative stable sedimentation processes in the muddy area during the past 100 years and the northward expansion of this muddy area.