Abstract: To ensure the track of the deep buried hill horizontal wells can effectively enter the buried hill reservoir and drill in the favorable reservoirs as geologists desired, we have established a method for designing the hole deviation angle of horizontal well for detecting the surface of deep buried hills. Taking the designing of the well trajectories starting from the high position of the buried hill to the low position, where entering the buried hill reservoir is relatively difficult and the favorable reservoirs tend to be drilled through as the research object, we have analyzed the relationship of the formation dip, reservoir thickness, tool angle building capability, and the designed inclination for detecting the surface of buried hills; considered the main influence factors, such as the angle between formation dip and designed azimuth, prediction error of the formation dip, the error of thickness prediction of the profitable reservoirs, etc.; established the model for calculation of the hole inclination for detecting the buried hills and have applied it to the design of horizontal wells into buried hills in Jidong Oilfield. The actual drilling shows that the design method has achieved the goal of effectively detecting the buried hill surface and drilling along the profitable reservoirs as the geologists desired.