This thesis discusses the relationship between teachers and students’ academic achievement. The characteristics of teachers have evolved with social changes; thus teachers of different generations have different patterns of traits. Empirical results show that among the factors people usually employ to judge a good teacher, for instance, MA teachers, normal university graduates, teachers with teaching credentials, female teachers, subject-majoring teachers, and teaching experiences, only few of them are relevant to academic performance. The major of teachers is the most important characteristic consistently, and longer teaching experiences sometimes improve pupils’ learning according to subjects. Public schools are associated with poorer academic outcomes than private schools. However, teacher fixed effects suggest that teachers still play pivotal roles in determining students’ performance, but through unobserved traits.