Through attending service agency accreditation, special inspection on the work specification, and technical report examination, the implementation conditions of the Work Specification in Occupational Health Technical Service Agencies were investigated in selected service agencies. The specification was well publicized in the included service agencies and expressed in quality system documents, indicating satisfactory implementation conditions, which effectively promoted the quality of occupational health technical service, though service performance, information publication, hazard identification, field sampling management, and participation in external proficiency tests required further improvement. Therefore, it is suggested to clarify performance requirements, establish a unified information management system, strengthen special supervision and inspection, and elaborate the requirements of a part of items in the work specification, so as to effectively improve the quality of occupational health technical service.