The purposes of this study were to observe the teaching behaviors of a chemistry majored junior high school physical science teacher in the classroom, explore the behavioral changes in teaching practices of case teacher’s under the influence of the scaffold (case teacher watched her teaching videotape alone), analyze the characteristics of these behaviors from the angles of teching dimension in “The Evaluation Instrument of Teaching Competencies on Junior High School Physical Science Teachers”, make the comparison of the similarities and differences of the teaching behaviors before and after scaffolding, and describe the unique qualities of these changed behaviors. The results of this study were concluded that case teacher awared the importance of students’ involvement in the teching contex, and self-awareness led to the behavioral changes with perceptual shift.