Personnel who are engaged in law teaching and research in law departments and law research institutions of colleges and universities and have senior professional and technical titles may apply for part-time lawyers with the consent of their units. Civil servants may not concurrently serve as practicing lawyers.
Part-time lawyers must practice in law firms. If they are only qualified as lawyers and have no office, they can't represent cases as lawyers.
For example, a university law professor can go to a law firm as an intern, become a lawyer of the law firm, and handle cases. At the same time, he has to substitute in the school where he works.