Library management is a complicated and mechanical work. Many librarians suffer from mental health problems, which affects their professional responsibility. This paper aims to unveil the positive impacts of a good mental health on the professional responsibility of librarians. First, a questionnaire survey was carried out in two Chinese provinces. Through descriptive analysis of the collected data, the author evaluated how factors like gender, major and working age influence the mental health and professional responsibility of librarians. Then, the multi-ordered Logit model was adopted to discuss the impacts of six 6 influencing factors (work place, age, job title, monthly income, physical health and development prospect) on the mental health and professional responsibility of librarians. The results show that gender, major, and working age of the librarians have significant impacts on their mental health and professional responsibility; the six influencing factors greatly promote the mental health and professional responsibility of the librarians. This research sheds light on improving the mental health of librarians and enhancing their sense of professional responsibility.