Abstract: By using casting thin sections,scanning electron microscopy(SEM),high pressure mercury injection,Xray diffraction and other experiment testing methods,the physical properties study of Chang 6 reservoirs in Wuding area,Ordos basin was carried out,and the deposition and diagenetic effects on physical development were analyzed.The results indicate the lithology of the study area is mainly of gray fine arkose sandstone,the reservoir space types are mainly of original intergranular pores and dissolved feldspar pores,and the reservoirs can be divided into three parts based on capillary pressure curve,namely dissolved-intergranular pore,dissolved pore and intergranular micropore.Porosity and permeability are positively correlated,and the porosity and permeability of different pore types have obvious different zoning.Sedimentation and diagenesis jointly affect the evolution of reservoir properties,the effect of sedimentation on reservoir physical properties is mainly due to the muddy content.Compaction has a negative correlation with porosity and the cementation has a good effect on the physical properties.The dissolution effect in the study area is not obvious,which has little effect on the physical properties.