Abstract: The modeling method for 3D stratum is one of the key problems in the visualization of strata,which includes two kinds of method,i.e.,surface modeling and volume modeling methods.A new volume modeling method for 3D stratum with block theory was discussed.The internal structural surfaces and the boundary surfaces within the stratum area were considered as virtual fracture surfaces of rock mass,and these fracture surfaces would cut all the strata areas into a certain amount of limited blocks;the left of the virtual rock masses would be cut into a certain amount of limitless and limited blocks.By use of the vector analysis method of block theory to identify the limited blocks in the strata area,and to compute their coordinate in the top of the blocks and sequence them in every side,the construction and cutting process of 3D strata were finished.Thus,strata blocks could be plotted by Open GL and then,3D visual strata were realized.