Soil microbial diversity and community structure under continuous tobacco cropping were analyzed by using Biolog microplates. The results showed that the average well color development (AWCD) of soil microbe in 7a continuous tobacco cropping were lower obviously than in rotation; the indices of richness, Shannon-Wiener and Simpson’s diversity of microbial metabolic diversity of continuous tobacco cropping were all significantly lower than those of maize-soybean-tobacco or soybean-maize-tobacco rotation; and the functional diversity index of soil microbial community under 7a continuous tobacco cropping was lower than under 2a. The utilization of carbon sources by soil microbes was lower in continuous cropping than in rotation. It suggested that continuous tobacco cropping reduced the diversity of soil microbial community structure and function.