Landslides anddebris flows in Langcangriver basin have the characters of widespread distribution andfrequent occurrence. The navigation construction of hydroelectric power station and reservoir, cities andtowns, as well as mines and farmland in the basin, have been seriously affected. After detailed investigationsin detail in recent years, it has been confirmed that there are more than 490 landslides and 662 debris flowravines in the Laneang Watershed in Yunnan Provience. Among them, about 60% of landslides and debrisflow ravines conceny trates in the middle - lower reaches of Laneang River. Landslides and debris flows inthis area are the result of a complex interaction of geological and geographical environments, and have a vari-ety of causes; weak rocks, rugged topogtaphy, heavy rainfall, and human activities.In order to reduce landslide and debris flow disasters, earth - science technology has been applied wide-ly for the prediction. One of the most important work is hazard zoning of Landslides and debris flows, whichis concerned with establishing the general probability of slope instability and zones of differing grade of threatby evaluating the triggering factors and recorded landsliding. Therefore, hazard zoning of landslides and de-bris flows is significant to provide useful information for different applications, such as planning and construc-tion, as well as stabilization and maintenance in the Laneang River. In this paper the author discussed theapplication of three methods for assessing landslide and debris flow hazards in the study areas. Trie final zona-tion results show that the high hazard area takes up 19.3 % of total study area of 57 530 km², the middle haz-ard area is 26.2% , and the low 25.8% .