The technology of using phase model to establish sedimentary geology model has become mature,but for volcanic gas reservoir,the single phase modeling method still has limitation.Therefore,in view of the overlying volcanic single control characteristics in Changling gas field,the authors,from the perspective of "volume control",used boundary point encryption projection correction,varied azimuth,weighted average and local grid encryption technology to establish three-dimensional geological model which could effectively solve the modeling problems such as the volcanic gas superimposed relationship,structure abnormal point,communication and resolution.This body control modeling technique was applied to horizontal well design and geo-steering,and realized the three-dimensional trajectory control,which can effectively improve the ratio of gas drilling in horizontal well.