In this study, it was aimed to determine the reflective thinking levels of prospective teachers and the change of their reflectivity levels within the teaching practicum process. For this purpose, the blog postings, which written by the prospective teachers at different themes, were analyzed. Within the scope of the study, reflective thinking levels were discussed based on the six different criteria with the following titles: Attending to feeling, sharing personal experience, analysis and meaning-making, depth of reflection, language use and writing quality, use of textual evidence and historical context, and transfer of knowledge. In this study, the document analysis method was used as a data collection technique. The study was carried out with 37 prospective teachers, attending Teaching Practicum in the Department of Computer Education and Instructional Technology (CEIT) of a state university in Ankara, Turkey. Prospective teachers wrote about their teaching experiences throughout teaching practicum on their blogs. Blogs were evaluated with the help of the reflection level rubric, which prepared by the researchers. It was concluded that the lowest reflection level emerged with regard to the use of textual evidence and historical context criteria and that less reflective blogs were, in almost all criteria, with respect to the overall evaluation of the course (Theme-5). In the last section, further results and related recommendations are mentioned.