The terrain in the virtual realistic environment will determine the scene generation level of realism. It has been a hot topic in computer graphics. In this paper, the analysis of the current generation of multi-terrain texture mapping method is carried out firstly. At the same time, the advantage and disadvantage of the method is pointed out. A new means is put forward. It is that while the gray images are proposed to provide terrain height field constraints, the image intensity information generated by the random noise is used as constraints to determine the random distribution information on different texture of terrain. At last, a realistic terrain using OpenGL Library Standard in Win32 console application is developed which is close to the natural environment with a high application value.