In an era where teachers are increasingly expected to perform at their level best, issues of self-efficacy and professional development continue to be an area of continuous debate. A random sample of primary and secondary school teachers in five cities in mainland China was selected to respond to the self-evaluation questionnaire, and 300 valid questionnaires were collected. The research was carried out to (1) investigate the levels of self-efficacy of music teachers in primary and secondary schools, (2) determine the factors that influenced music teachers' self-efficacy, and (3) explore the relationship between teachers' self-efficacy and professional development. The data were analysed using descriptive statistics, T-test, analysis of variance, and regression. First, the results showed that the mean value of music teachers' self-efficacy was 7.16. Second, the middle school teachers reported lower self-efficacy compared to teachers in the primary schools. Third, although teachers aged between 20 to 50 years old reached their highest level of self-efficacy, it decreased to a lower value after an extended period. Additionally, the study also revealed a significant difference in self-efficacy among teachers with different teaching experiences. Although educational backgrounds, gender, and training hours did not influence self-efficacy, a positive correlation was reported between self-efficacy and professional development. Prospective research might better consider developing music teachers' self-efficacy and education across primary and secondary schools.