This article focused on a deeper analysis of pre-service teachers' observations of video lessons based on the authentic classrooms across three stages in eight sessions in order to reveal their changes in the abilities to understand pedagogical content knowledge and the effects of specific observation frameworks introduced in the observation sessions. With those aims, we developed the coding schemas at the content and the method level to analyze the pre-service teachers' observation reports and reflections. It was found that the video lesson analysis based on the authentic classroom teaching has a great potential to support pre-service teachers' professional learning with the appropriate guidance. (Contains 7 figures and 2 tables.) [The outcome of this paper is a part of the achievements of the project "The Development and Application of a Method to Research Classroom Based on Discourse Analysis" (B12031) funded by Shanghai Municipal Education Commission, and the project "The Development and Application of a Method to Research Mathematics Classroom Based on Discourse Analysis" (No. SK201209) funded (2012-2013) by Shanghai Normal University.]