September 12^th to 13^th, the 20^th conference of the occupational disease branch of Chinese Medical Association for preventing and curing occupational disease was held in Gui yang, Gui zhou province. Li Qiang, the vice-president of the hospital and the director of Occupational medicine, hosted the special subject for Youth Assembly. The conference invited Mao Lijun, the vice director of Occupational medicine, and doctor Zhang Yanlin, Guan Li, to deliver a speech of the special subject.