Abstract: According to the demand of large hole diameter for coal mine gas control, the one-step holing technology and equipment of ø200 mm directional drilling were developed, the optimized method of strong-pull/push system was put forward, and the researching method of output characteristics of double-pump large-flow mud system was concluded.Meantime, the one-step holing technology was tested. The technology and key parameters were proved to be reasonable, and the technology was proved to be feasible. They provided a theoretical basis for the research and development of ø200 mm directional drilling equipment and drilling construction.