Aiming at the problems of large gas emission in fully mechanized caving face and gas overrun at upper corner in Wangjialing coal mine, directional drilling machine and equipments are applied and directional drilling technology are used for gas extraction by high-position directional drilling. Based on the analysis on the law of gas migration in the mining process, large number of field practice is completed. The trajectory layout parameters of the high-position directional drilling hole suitable for Wangjialing coal mine is put forward. Upper corner gas overrun is effectively solved.