Soil microorganisms are an important component of ecosystems and play an important role in the succession of new volcanic environments and vegetation. Furthermore, vegetation type is one of the most important factors influencing the functional diversity of soil microbial communities. However, the influence of vegetation types on soil microbial diversity during the process of vegetation succession, especially primary succession, remain poorly understood. Accordingly, the present study used a spatial, rather than temporal, approach to investigate the differences and changes of soil microbial community function in different stages of primary succession and to establish a basis for studying co-evolutionary relationships between soil microbial community function and environmental factors in the new volcanic lava platform. The aim of the study was to investigate the microbial characteristics of soil at different successional stages; Biolog microplate analysis was used to investigate the functional diversity of microbial communities associated with five typical vegetation types (i.e., moss, herbs, shrubs, elfin woods, and mixed broadleaf-conifer forest) at a new volcanic lava platform in the Wudalianchi area of China. Vegetation type had a significant effect on the functional diversity of the soil microbial communities. The average well colour development, which reflects soil microbial activity and functional diversity, increased with increasing incubation time and varied as follows:moss > mixed broadleaf-conifer forest > elfin woods > herbs > shrubs. The soil microbial diversity indices of the shrubs were significantly different than those of the other vegetation types. Principal component analysis identified two principal component factors that were related to carbon sources and explained 56.24% and 29.59% of the variance, respectively. Differences in the utilization of carbon sources by the soil microbial communities of different vegetation types were mainly caused by amino acids and carbohydrates containing phosphate rest, which explained 47.51% of the total variation. Redundancy analysis showed that available phosphorus, NH₄⁺-N, C/N, and pH had significant effects on microbial functional diversity. The degradation of carboxylic acids, amino acids, esters, and amines was more susceptible to environmental factors. These findings provide a reference for future studies regarding the complex interactions between vegetation type and soil microbes under different states of vegetation succession.