In order to provide reference for the development of community psychiatry in China which is still in the initial stage, we studied in this paper the historical conditions and the process for the realization of the “psychiatric sector treatment mode” in France. We considered that the new development of psychiatry after the middle of the 19th century and the “institutional psychotherapy”, which was constructed by psychiatrists after the second world war from the successful experience of Saint-Alban Mental Hospital，provided scientific and technological support for the realization of this service. At the same time, in order to promote the “institutional psychotherapy” and increase its political influence, educational training that they gave to psychiatric nurses, the young psychiatrists have won the resources and support of society for the application of this treatment. At the end of the article, we made a brief presentation and summary about the actual structure and operation of the “psychiatric sector treatment mode” in France.