This study aimed to understand an elementary teacher's multicultural teaching belief, her operational curriculum, and the factors influencing the gap between teaching belief and operational curriculum. Through the qualitative methods, this study chose a teacher and her sixth grade class as the study participants. The researcher utilized participant observation, in-depth interview and documents analysis to collect data. The study found that the teacher had firm multicultural teaching belief though, the teacher's multicultural teaching belief differed from her teaching practice. The gap resulted from some factors, such as curriculum goals, heavy teaching loading, and teacher's perspective in curriculum. However, the teacher kept improving and self-reflecting on her multicultural teaching belief and her teaching profession during the teaching process. Therefore, in order to push the development of multicultural education, not only should we help teachers build the multicultural teaching belief, but also should we reform the structure of school curriculum and teaching practices of teachers. So that an authentic multicultural educational environment can be built and modern citizens with multicultural perspective will grow.