This research project analyzes how teaching experience in the classroom contributes directly to the professionalization of the students from teaching profession. During the teaching training, students are part of an experiencial learning which provides them with new elements in context, those that are impossible to learn during the theoretical classes in the Education faculty classrooms. During this teaching training in the field, the future teachers are able to find three professional demands such as to contextualize, to negotiate the complexity and to take immediate decisions. This research project contributes with relevant reflections in order to improve the practical teaching training.