Objective: To assess the effectiveness of a psychological flexibility training course based on the Acceptance Commitment Therapy (ACT) DNA-V model in enhancing psychological flexibility and career adaptability among high school students, and to offer a reference for psychological health services. Methods: Collaborating with a high school in Chengdu, 110 second-year students were randomly assigned into three groups: a DNA-V face-to-face group (33 students), a DNA-V online group (40 students), and a control group receiving standard psychological education (37 students). The intervention consisted of a six-session course, with assessments using the Avoidance and Fusion Questionnaire for Youth and the Career Adaptability Scale conducted before, one week after, and two months after the sessions. Results: Data analyzed via linear mixed models showed that the face-to-face group experienced significant improvements in psychological flexibility and career adaptability at one week and two months post-intervention (P<0.01), with no significant changes noted between these two times. The online group saw no significant changes, and the control group s gains reverted to baseline after two months. Conclusion: The face-to-face DNA-V course effectively enhanced psychological flexibility and career adaptability for at least two months, underscoring its potential for integration into student mental health programs.