The coal bed methane is an important part of the Chinese energy. To finding some effect ways to collect gas during the coal mining process will increasing the using rate of coal mine and reducing greenhouse gas emission. The most effective way is coal and gas co-mining, and the main technology of the coal and gas co-mining are gas pre-extraction before mining, gas extraction of pressure relief, gas extraction of adjacent layer, gas extraction of goaf and top fractured zone, Gas extraction of excavation roadway and so on. Based on the technique system of coal and gas co-mining and the key problems existing in coal and gas extraction technology, to improve energy efficiency and reduce coal mine disaster.