a qualitative research was conducted on a presearvice teacher's practical knowledge. The data from observation, in-depth interview, journay and biography was collected during practice teaching. This study finds that preservice teacher really has practical knowledge during practice teaching. Secondly' the preservice teacher's practical knowledge include 「 the goal of education 」「 teacher's role 」「 the method of instruction 」「 children 」. Thirdly' the preservice teacher's images are 「 Let children learn and grow happily. 」「 Teacher should be fair. 」「 Teacher always need to renew herself. 」「 Teacher has a good relation with students. 」「 It is good teaching to respect each child. 」「 Don't give up any student. 」 Fourthly' the origan of images have the relation with her family life, her school experiences during children and teenages, some important others, her social work and her characters. Fifthly, her negative experiences of the primary school is the most influence of the factors of her personal practical knowledge. Sixthly, her images has been shattered during practice teaching. But the preservice teacher says that she has gotten a lot of benefits from the research, such as reflecting about her teaching and more understanding herself as a teacher.