The nature of the discipline of psychotherapy and the ethical issues in psychotherapy practice have been central themes that have provoked reflections among psychotherapists. This article begins with a brief introduction to the life of German systemic family therapist Helm Stierlin and his linkage with the Chinese-German Advanced Continuous Training Project for Psychotherapy, followed by a focused review of Stierlin’s reflections on the challenges facing modern science and the ethical difficulties faced by family therapists. He reconsidered the identity and role, professional quality, ethical responsibility and epistemological position of family therapists, and put forward his personal opinions. Stierlin believed that an epistemological reflection is necessary. He also carried forward the art of family therapists. Even today, nearly half a century later, Stierlin’s thoughts and opinions still contain profound significance of the times, giving people alarm and inspiration.