Soil microbial carbon use efficiency (CUE) represents the proportion of microbes allocate carbon taken from the environment to their own growth. It is a synthesized index of ecosystem C cycling, because of the crucial role that microbes play in the decomposition and stabilization of soil organic C. Changes in vegetation types stronly influence soil physical and chemical properties and the composition of soil microbial community, and hence microbial CUE. Studying the effect of vegetation type conversion on microbial CUE could act as a lens through which to resolve the link between vegetation and ecosystem C cycling, and could provide the foundation for assessing the changes in soil quality caused by vegetation type shift. Therefore, it is of great theoretical and practical value to study the effect of vegetation type conversion on microbial CUE. Based on the systematic review of related literature, we summarized the changes in soil microbial CUE as a result of vegetation type conversion, as well as affecting factors and underlying mechanisms. At present, Most empirical studies concerning the changes in microbial CUE due to vegetation conversion mainly involves the following 5 types:primary forest to secondary forest, natural forest (primary forest and secondary forest) to plantaion, woodland to grassland, the conversion between woodland and agricultural land, and the degradation or restoration of grassland. Soil microbial CUE generally declines during the conversion from natural forests, including primary and secondary forests, to plantation, and from woodland to grassland, despite the microbial CUE would recover slowly to its original level as the vegetation develops after the conversions. The more mature the vegetation was, the more drastic the change of CUE would be when it changed. In addition, there are uncertainties in change directions and large variations when farmland abandonment and agricultural expansion are involved in conversion. The changes of CUE due to vegetation type conversion mainly driven by vegetation, edaphic and microbial factors and their interactions. However, many ambiguities still remain in the impact mechanism of vegetation type conversion on microbial CUE, such as the impact of plant diversity, litter quality and root, and many edaphic properties, e.g. soil temperature and pH. What's more, the research on how microbial community drives CUE change is very weak. Besides, different methods, e.g. CUE indices, sampling seasons and soil layers, used in studies affect the evaluation of CUE changes. Future related sudies are needed to better understand the change dynamics of microbial CUE in different soil layers after vegetation conversion in a wide range of vegetation types and climatic zones by using the direct CUE determing methods, and particularly the mechanisms underlying the CUE dynamics.