The professional identity of grass-roots civil servants is of great significance to the team construction of civil servants and the modernization of national governance. Through a questionnaire survey of 760 civil servants, this study finds that the professional identity of grass-roots civil servants includes three dimensions:professional behavior input, professional development identity and professional value identity, showing a circle structure with value identity as the core, behavior input as the outer layer and development identity as the middle layer; the level of professional identity of grass-roots civil servants is close to a higher level, but the level of professional development identity is low; different types of grass-roots civil servants show some differences in professional identity, among which the professional identity of young civil servants is significantly lower than that of middle-aged and old civil servants, and that of lower rank civil servants is lower than that of higher rank civil servants. Further analysis finds that the professional identity of grass-roots civil servants can positively predict job performance, and negatively predict turnover intention. On this basis, this study puts forward some suggestions to improve the professional identity of grass-roots civil servants.