It is needed to real-timely know microtopographical features of mining area during mining submarine cobalt-rich crust. This paper changes the measured altitude data of submarine cobalt-rich crust mining area into interval [-1,1] by linear transformation, then, in the light of fractal features of submarine microtopography, adopts conventional midpoint displacement method to make the fractal interpolation to altitude data of submarine microtopography in order to divide the triangular grid, finally, based on the OpenGL 3D graphics standard programs to map the submarine microtopography. The experiment has verified that algorithms used for the programming is succinct and highly efficient, the program interface is friendly, and simulated submarine microtopography is lifelike. This provides an approach to realize the visualization of submarine microtopography.