Abstract: An experiment was carried out in southern Anhui province to study the types and population of soil microorganism during life cycle of tobacco growing under four types of soil systems (sandy soil on river beach, alluvium fine sandy soil, paddy clay soil, and alluviun sandy soil). The major results showed that both in rhizosphere and non-rhizosphere soils, the bacteria, fungi and actinomycetes were the major types of soil organisms, which were more than 95% of the total soil organisms. During the whole growth cycle of flue-cured tobacco plant, the microorganism population in rhizosphere soil was higher than in non-rhizosphere soil, the differences in population and diversity index of each soil microorganism were observed in different ecological conditions, and in most of case, there was a positive correlation between the soil microorganism population and soil nutrient contents.