The health certificate is the proof of preventive health examination, which proves that the examinee has the health quality to engage in the prescribed business. Health certificate mainly involves six diseases in five industries, which largely protects the health of employees and clients. According to the national health laws and regulations, the operators of food and drinking water, personnel directly engaged in cosmetics production, personnel who directly serve customers in public places, hazardous workers, radiation workers and students at school are given pre-post, in-post and post-post health examinations.