Abstract: Based on thin section observation, analysis on SEM, physical property and mercury injection and laser scanning confocal microscope observation, the petrological characteristics, reservoir space type, physical property and pore throat distribution are studied for the tight sandstone reservoir in the second member of Kongdian formation in Cangdong sag of Huanghua depression, Baohai Bay basin. The result shows that the reservoir in the second member of Kongdian formation is dominated by lithic quartz sandstone and lithic sandstone, and the reservoir space is mainly composed of secondary dissolved pores and intercrystalline micro-pores, containing a few residual primary pores and fissures. The porosity and permeability of the reservoir average 7.71% and 0.59 mD, respectively, indicating that the reservoir belongs to super-low porosity and extra-low permeability reservoirs. The reservoir pore throats have relatively poor structures and are mostly distributed separately, so the pore connectivity is poor. The reservoir pore radiuses are similar with the most ranging from 100 to 200 μm. Pore throat radiuses vary largely with the most in micron-nano scale. The filtration capacity of the reservoir is mainly controlled by radius, frequency and distribution pattern of pore throats. Some treatment technologies should be adopted to protect the pore throats in the tight sandstone reservoirs in the second member of Kongdian formation and better development effects can be gained