Abstract: Taking Chang?6 tight sandstone reservoir in one field of mid?eastern Ordos basin as an example, with many experimental means such as FE?SEM, rock and cast sections, mercury injection and NMR, etc., this paper discusses in detail the pores and throats features in tight sandstone reservoir and suggests that the composite effects of pores and throats are significant to the development of such a reservoir.The static geological model for this reservoir can not well match with the micro?pores and throats by cell unit size, which is the primary cause resulting in limitation of reliability and accuracy, while using mean cell unit size of micro?pores and throats could more directly and properly characterize the heterogeneity of the tight sandstone reservoir