The main purpose of this study was to explore teachers' teaching beliefs, perceptions of Technological Pedagogical Content Knowledge (TPACK) and their teaching self-efficacy. A total of 200 teaching Chinese as a second language teachers (TCSL) of Taiwan were participants in this study for the data collection. In this study, three questionnaires were used, including teacher's teaching beliefs, the teachers’ perceptions of Technology-related Pedagogical Content Knowledge (TPK/TCK/TPCK) and teachers' teaching self-efficacy. As a result, the confirmatory factor analysis showed that the three questionnaires used in this study were valid and reliable. Besides, according to path analysis, the result indicated that the teachers with constructivism belief tended to have more perceptions of all the Technology-related Pedagogical Content Knowledge; on the contrary, the teachers with traditional belief showed that they tended to have fewer perceptions toward TPCK. Furthermore, it was found that teachers’ TPK could positively predict all of their teaching self-efficacy; their TPCK could positively predict their subject content self-efficacy and their TCK can positively predict their Teaching outcome expectancy. All in all, there was a positive relationship between TCSL teachers’ constructivism belief and their Technology-related Pedagogical Content Knowledge. Cultivating TCSL teachers’ constructivism belief was suggested in TCSL teacher development for enhancing their perceptions of TPACK and their teaching self-efficacy.