Based on the stationary distribution, the spatial dynamic behavior of a class of stochastic chemostat models with parameter perturbations is studied. Firstly, the complete expression of the probability density function of the stationary distribution of microbial population is obtained by using the basic theory of differential equation. Then, by analyzing the shape of the obtained stationary distribution density function, it is found that the noise changes the dynamic behavior of the original deterministic chemostat model to a large extent. In addition, the maximum probability equilibrium point will change with the change of noise intensity, presenting a relatively complex dynamic behavior. Finally, a group of experimental data in the literature are used to simulate and analyze the results, which are consistent with the theoretical results. The main purpose of studying the chemostat model is to study the survival and distribution of microorganisms in it. In-depth study on this problem can provide relatively complete theoretical basis for relevant practitioners.