The purpose of this case study is to interpret a teacher's thoughts on teaching, her reflection on preparation and performance as well as her decision-making in teaching English. An elementary school English teacher was asked to be observed and videotaped for three months. Stimulated recall interview was used as a method to collect data and understand her reflection in three phases of the process. The findings of this study are as follows: Teaching preparation: Based on her own beliefs and insistence about English teaching, the teacher considered and decided how activities were developed in the teaching process. Teaching performance: The teacher had dilemmas and confusions with adopting activity-oriented approach. Reflection on teaching: The teacher had a multiple-dimensioned reflection on her teaching, including teaching performance, activity designing, teaching environment, teacher's role and her personality. The case study helps us interpret the relationship between the teacher's thoughts on teaching and performance. It provides the English teacher with an environment of support and dialogues, letting her regain her passion for English teaching.