Second-line personnel refer to civil servants who resign from leadership positions or no longer undertake first-line tasks. In the reform of supervision system, second-line personnel can participate in the supervision work, but it does not mean that they can directly evaluate the supervisors. The selection and appointment conditions of supervisors are strict and need to meet the requirements of political quality, professional ability, legal literacy and moral quality.

Although the second-line personnel do not directly hold leadership positions, their work experience and work level can still support the supervision work. In practical work, second-line personnel can hold certain positions, such as supervisors and assistant supervisors, but they are not supervisors.