Objective To guide occupational health inspectors in accurately identifying the key points of law enforcement and case management during the supervision of occupational health technical service institutions, standardize the collection of evidence for illegal activities and the application of legal provisions, ensure the proper execution of administrative penalties, and provide insights for handling cases related to the supervision and law enforcement of occupational health technical services. Methods This study analyzed the key points of evidence collection using an example case involving an entity that engaged in occupational health test and evaluation technical services without obtaining the required qualifications for occupational health technical service institutions. Results The key points of evidence collection primarily included: evidence proving the qualification of the penalized subject, evidence proving jurisdictional authority, evidence proving the conduct of occupational health technical services, evidence proving the absence of an Occupational Health Technical Service Institution Qualification Certificate, evidence proving illegal gains, evidence proving the circumstances of the violation, and other evidence proving the legality of administrative procedures. Conclusion In the implementation of administrative penalties by occupational health supervisors, standardized investigation and evidence collection constitute a critical component of law enforcement and case handling. Sufficient evidence collection and accurate application of the law are indispensable for safeguarding public health and societal interests against infringement.