In order to observe the changes of the causes of death among the residents in Gansu, mortality and years of porential life lost (YPLL) are used in this article to analyse the data of causes of death in 1990-1994. Data indicates that the average mortality of residents was 591.98 per 100,000. The main sequence were as below: respiratory diseases, cardiorasculor and cerebrovascalar diseases, neoplasms, injuries and pediatric diseases. Chronic diseases take up 74.4% of an mortalities. Average YPLL was 55.84/1000. YPLL sequence was as follows: injuries, neoplasms, respiratory system diseases, infectious diseases, cardiorascular diseases.