Principals’ leadership and teachers’ teaching are the key to school effectiveness. It is an important issue that principals can promote the professional development of teachers through effective leadership and pooling of consensus among members. In particular, with the promulgation of three experimental education regulations, schools face many challenges and must be properly responded to. Moreover, the implementation of the new curriculum is an important issue in the education sector in Taiwan in recent years. To achieve this goal, the concept, attitudes and techniques of teachers’ teaching must be changed, and this depends more on the role of the principals’ instructional leader, providing teachers with support in teaching which can help teachers to enhance teaching quality and students’ learning achievement. This article mainly explores the issues of principals’ leadership and teachers’ teaching support. There are three parts in this paper. Firstly, the relationship between principals’ leadership and teacher teaching support was analyzed. Secondly, the importance of principals’ leadership and teacher’s teaching to the implementation of the new curriculum was explored. Finally, the strategies for strengthening principals’ leadership and implementing teacher’s teaching support were proposed.