In recent years, although the overall development of the teaching workforce in China's vocational colleges has made significant progress, how vocational colleges should carry out the professional capacity building of "dual-qualified" teachers remains an area of exploration. This study collected 9,259 teacher professional development summary texts from 500 vocational colleges across the country and, based on theoretical sampling, conducted in-depth interviews with 16 participants, including vocational college teachers, administrators, students, and relevant enterprise representatives. Ultimately, a corpus of 8.29 million words was compiled. After analyzing the corpus using NVivo software, the following major issues were identified regarding the current professional capacity building of "dual-qualified" teachers in vocational colleges: insufficient institutional support, gaps in professional capacity development, and the urgent need for improvements in evaluation and incentive mechanisms. To better serve society with high-caliber, skilled technical professionals, vocational colleges need to address these practical challenges. This requires enhancing policy support for vocational teacher professional development, building a "dual-teaching qualification" lifelong professional development system, and improving the evaluation and incentive mechanisms for advancing teachers' professional capacities.