In recent years, debris flows have been a major kind of natural disasters in Taiwan. Debris flow can be divided into several categories, such as granular flow, mud flow, etc. Mud flow can often be simulated by Bingham flow theory. This study started from steady and uniform flow. Then, Perturbation method is used to analyze if it is stable, and I have applied a small perturbation on the wall of channels. The final step is to apply different parameters in the experiment to analyze the result. From this thesis, we know that no matter what ratio of channel width to channel depth, gravity to shear, it may be unstable. But if we assume that the wavelength of perturbation is very short, it’s stable or not will depend on the ratio of gravity to shear. On the other hand, if we assume the wavelength of perturbation is very long, it will be stable.