Abstract: Aim To study the use of virtual reality technologies and 3D graphic methods in military C 3I systems for the simulation of terrain in battlefields Methods Some methods used in a prototype system for terrain modeling are introduced,compared,and analyzed,including contour line transformation,digital image processing,fractal method,level of details,and GIS Improvement for these methods are discussed Results and Conclusion The integration of terrain data into military virtual environment is well accomplished in the prototype system by using the discussed methods in combination This gives guidelines for the design of such systems