This paper comprehensively uses coal petrology, coal chemistry, biology and other research methods to carry out microbial flotation desulfurization experiments on typical high sulfur coals in Shanxi, China. In order to study the best desulfurization effect under certain conditions, also to make evaluation and analysis. The results show that microbial pretreatment has an effect on the desulfurization rate of coal samples, but it has different effects on different coal samples. The microbial flotation desulfurization rate of high-sulfur coal is affected by various factors, including pretreatment time, particle size of coal samples, morphological sulfur occurrence characteristics, morphological sulfur distribution characteristics, coal ash content, etc. Overall, most samples reach the maximum desulfurization rate when the pretreatment time is 20 minutes. The smaller the particle size of the coal sample, the better the desulfurization effect. There is no significant correlation between the degree of coal metamorphism and the microbial flotation desulfurization rate. The occurrence characteristics of morphological sulfur and the ash content have a great influence on the desulfurization rate. The total sulfur removal rate is positively correlated with the total sulfur content in the coal and the proportion of pyrite sulfur in the coal to the total sulfur content. The ash removal rate and the desulfurization rate are also significantly positively correlated.