With the innovation and progress of Internet technologies, the application of three-dimensional (3D) simulation technologies in games and animations has become increasingly important. In response to the lack of detail and the distortion of the mountains generated by the random midpoint displacement method, this paper proposes a method of generating simulated 3D terrain environments based on the OpenGL technology and the Perlin noise algorithm. The elevation maps generated by the traditional Perlin noise algorithm are relatively flat. Therefore, they are optimized with the fractal and turbulence algorithms, which produce obvious conflicts that are more in line with the characteristics of the mountains. For the transitional fault phenomena in the process of terrain image mapping, a layered sampling strategy is adopted to make the image more natural. In the case of added light, the plane normal vector is obtained through the multiple binary averaging algorithm, which delivers a smoother mountain light representation. The experimental results show that the method not only realizes the 3D grid construction of 3D terrain but also shows a favorable simulation effect.