Aiming at the cataclastic band developed in lithic quartz sandstone of K2h Formation in Yuan’an Graben，based on the detailed study of its macro-characteristics and experimental analysis data，the micro-characteristics of the cataclastic band are described，and the deformation mechanism is analyzed and discussed in detail. The results show that the deformation band in the study area has the characteristics of shallow to middle burial depth，in which cataclastic band is mainly developed. The most common modes of grain breakage are multi-point contact and complete fragmentation. The micro-heterogeneity is characterized by the inhomogeneous deformation of a single cataclastic band along its strike，the relatively homogeneousdeformation of a single cataclastic band perpendicular to its strike，the strengthening of the cataclastic band caused by the strong cataclastic flow and the inhomogeneous inner-structure of the cataclastic bandclusters，which reflects the formation of the cataclastic deformation band，and also indicates that its deformation mechanism changes from cataclasis to cataclastic flow. The temporal sequence of the deformation zone is from the cataclastic core formation to medium-degree fragmented cataclastic band to cataclastic band with complete crushed grains to cataclastic band clusters. Finally，a sliding surface may be formed along a certain cataclastic band. In the field，it is common to find the medium-degree fragmented cataclastic band clusters and completely crushed deformation band clusters. Compared with the host rock，the porosity and permeability in the completely crushed deformation band clusters are seriously decreased，which can be reduced by 4 orders of magnitude in actual measurement，and it is likely to have a great impact on fluid flow.