Ground L-shaped well gas drainage and pressure relief is an important technical means for gas drainage in coal mining areas. In response to the current problems of low drainage efficiency, difficult well completion and large difficulty in well deviation control during the gas drainage process of ground L-shaped horizontal wells, the technical principle of L-shaped horizontal well gas drainage is analyzed and three key technical points, including well location deployment, key technologies for drilling and well completion, and negative pressure drainage technology, are summarized. According to the gas migration law, the L-shaped well layout range is optimized; the three-casing wellbore structure design is sorted out and proposed, the wellbore trajectory control technology is optimized, the anti-pressing directional drilling technology, well completion and well washing technology, and cementing technology of L-shaped wells are studied, and the L-shaped well drilling technology system is established. According to the characteristics of gas drainage and pressure relief by L-shaped wells, two negative pressure drainage modes and negative pressure drainage control management systems at different stages are proposed. The "flow rate guarantee and negative pressure variation" control method is adopted at each stage. The gas drainage effect of ground L-shaped wells in Huaibei mining area is studied and analyzed. The pure gas drainage volume of Guobei Coal Mine reaches 2.7×106m³, and the pure gas drainage volume of a group of L-shaped horizontal wells implemented in Zhuxianzhuang Coal Mine is up to 5875m³ per day, achieving safe mining. On this basis, the future development direction of L-shaped well technology is proposed, mainly including the precision of design parameters, precise control of horizontal section trajectory, large displacement horizontal well drilling, refined drainage management, and joint ground-surface L-shaped mining-induced well gas drainage technology.