Despite the growing focus on STEAM education in China, there remains a lack of understanding regarding the core competencies required of STEAM educators, as well as the preparedness of pre-service teachers to effectively implement STEAM education. To address the gaps, we developed a framework outlining the essential competencies for STEAM education. This literature-based framework identifies four key areas: (a) value appreciation, (b) knowledge mastery, (c) curriculum development, and (d) implementation and evaluation. Using this framework, we conducted a survey of 194 pre-service teachers to assess their competencies in developing and delivering STEAM education. The findings indicate that the respondents’ overall competencies in STEAM education need improvement, particularly in the areas of knowledge mastery and curriculum development. Variations were observed among the respondents from different backgrounds. The study concludes with a discussion of the implications for future research and practice, offering recommendations for better preparing pre-service teachers for STEAM education.