This study aims to explore integrating new teaching methods and interventions from acceptance-commitment therapy designed to improve the psychological flexibility of Chinese university students through a required university student mental health education course. Psychological flexibility is a protective factor for mental health. The low level of psychological flexibility is one of the reasons for the high incidence of depression, anxiety and other psychological problems at university. This longitudinal study used a pre and post-test design to test some freshmen in a particular grade at Huangshan University using the AAQ-II, CFQ-F and SCL-90. Then, a new teaching method was implemented in the courses. Systematic sampling was conducted at the end, with a sample of 287 subjects selected (M = 19 years, SD = 0.73 years; 46.6% male,53.3% female) and was followed up to analyse the psychological test data before the course teaching and after one year. The results showed that after controlling for gender, there was a significant difference between the pre-test and the post-test, with a substantial increase in the level of psychological flexibility (P<0.001), and essential psychological symptoms were significantly reduced (p<0.001). It is concluded that the new curriculum and teaching methods can dramatically improve psychological flexibility and mental health. Based on the core concept of improving psychological flexibility, reforms should be carried out in the required curriculum of Chinese university students' mental health education, incorporating new teaching methods and interventions to help students solve their psychological distress, alleviate psychological symptoms, and promote mental health.