Abstract: In order to research Dendrobium officinale rust pathogenic fungus and regularity of outbreak, the disease observation and investigation, collecting specimens and pathogenic identification were carry out in field and laboratory in 2014 at Longling County, Baoshan, Yunnan Province. The result were showed that the D.officinale rust caused by Coleosporium zanthoxyli, it was only distributed in Yunnan. Alternate hosts was unknown at present. The rust damaged D.officinale, D.thyrsiflorum and D.wardianum. It also caused early leaf decay and affectted growth and yield. It was a new disease on D.officinale which was the first time discovery in China.