Abstract: To elucidate occurrence and damage of sea-buckthorn dieback, the disease was systematically investigated and analyzed by fixed point, routine observing and large area surveying in Hexi district, Gansu Province. The results showed that branches were infected mainly by pathogen. Serious infected tree led to branches or tree dead. The main epidemic factors causing such disease were climatic conditions and the weak tree. Sea-buckthorn dieback usually happened early if temperature raised and rain fell early in Spring. The more rain fell, the more serious disease happened. Optimum temperature of sea-buckthorn dieback was about 25℃.The temperature below 20℃ or above 30℃ was against happening of the disease. The trees were infected seriously by the pathogen in the new and old sea-buckthorn mixed wood. Inefficient management and plenty of fruits were also one of main factors causing serious disease. Besides, sea-buckthorn dieback causing wounds on the bark were infected seriously by Plowvigneia hippophaeos, so sea-buckthorn shrinkage disease happening was relatively serious. It is the first report that sea-buckthorn dieback disease happened in Hexi district, Gansu Province. The incidence of sea-buckthorn dieback was higher and higher year by year.