Microbial traits are core attributes closely related to microbial survival, growth and reproduction. These attributes could reflect the microbial responses to environmental changes, and then affect species distributions, community assembly processes, and relevant ecosystem functions. There is a growing recognition that, compared to microbial taxonomic information, microbial traits could expand our understanding of microbial ecological processes and provide mechanistic explanations of ecological patterns at the scales of population, community and ecosystem. Here, we address important ecological themes based on microbial traits in recent years, including the classification and determination of microbial traits, functional diversity and applications, the relationship between microbial traits and species distribution and community assembly, the effects of microbial traits on biodiversity and ecosystem functions and the response of microbial traits to global change. Although previous studies on microbial traits have been extended to all aspects of ecology and promoted the research and development of various frontier scientific problems, there are still many opportunities and challenges. Thus, we also provide perspectives such as research methods and directions based on microbial traits.