Abstract: Porosity is an important physical parameter of seabed sediments. However, the traditional method for porosity acquisition remains insufficient. In this study, we measured the porosity of the sediment core SS4 taken from the along-shelf clinoform deposit in the East China Sea with a medical CT-Scanner, and extracted the CT numbers one by one in vertical direction. By comparison of the CT numbers with the porosities obtained from the tube method, an empirical formula is derived between CT number and porosity for the clinoform deposit in the East China Sea. It is found that the CT number is poorly correlated with the porosity acquired from the tube method, when the vertical composition of the core was inhomogeneous, owing to the texture inconsistency of samples. However, the empirical formula acquired from the core sections where occur high correlations between CT numbers and porosities should have higher reliability. Thus we recommend the CT scanning method as a fast and nondestructive method for measurement and observation of sediment porosities.