Abstract: Based on in-depth analysis of the Tianshui mountain geological hazards,through the methods of field investigation,experimental data and analysis the results of data,system research the main types of geological disasters and its causes in Tianshui Beishan.Based on the study of geological hazards genesis mechanism analysis and discussion,for further processing of the area of all kinds of geological disasters and provide theoretical guidance and the prediction of future occurrence of the study area geological disasters has a positive role in guiding and practical significance.Tianshuishi sudden geological disaster types have mainly landslide,collapses,unstable slopes,ground subsidence and debris flow five types,the geological disaster mainly distributed in the sunny slope in Beishan Tianshuishi,formed a number of landslide group ditch.Landslide types to hybrid,middle and small loess landslides primarily;The type of collapse to give priority to the person loess collapses.The main type of unstable slopes is loess,located mainly in the landslide or terraces front and human residential area.The ground subsidence mainly distributed in the landslide.Debris flow disaster,according to the material component belong to mud flow channel,according to the valley belong to hillside type form according to the fluid property belongs to dilutesex,according to the hydrodynamic conditions belong to heavy rains type.