Abstract: In the process of drilling construction, due to the influence of drill pipe weight, geological conditions and drilling technology, the actual drilling trajectory deviation is larger than the design trajectory. The deviation of drilling trajectory leads to the appearance of blank zone in the area covered by gas drainage boreholes, which affects the gas drainage effect. In order to master the distribution of the blank zone of gas pre drainage boreholes, the trajectory of gas pre drainage boreholes is measured by using the borehole trajectory measurement system. After the data processing of the trajectory measurement system, the 3D display of boreholes can be realized, and the offset of boreholes in different directions can be observed from different perspectives of 3D space, which provides data support for the hole filling of the blank zone of boreholes. According to 3d data and 3D results to show the distribution of blank drilling zone, targeted hole filling is carried out to improve the accuracy of gas elimination and ensure the safety of mine production.