Abstract：For the problems of safe and high-efficient exploitation in low permeability and methane-rich seam group，Huainan area was chosen as primary experiment base. And based on different coal seams and gas geological conditions，by means of rock mechanics，strata moving theory and “O-ring theory”，a series of engineering technologies on pressure relief gas drainage by mining the roof of the coal seams were built；and the technological system of gas drainage of pressure relief mining and integrated coal mining and gas extraction was established. The rules of rock strata moving，pressure-relieved gas moving，abundant zone of pressure-relieved gas，pressure-relieved zone and pressure-enhanced zone of mining seam were studied. The theory and technology of pressure relief gas in first-mined seam，gas in upward pressure relief seam，gas in downward pressure relief seam and pressure relief gas of surface borehole were studied. The theory and technology of pressure relief gas drainage were developed；and the problem of integrated coal mining and gas extraction was resolved.
