Abstract: In order to effectively overcome the problem of narrow density window drilling, increase drilling efficiency and reduce drilling cost, a set of fine controlled pressure drilling equipment has been developed domestically with proprietary right, which has realized the goal of accurately controlling down-hole annular pressure. This equipment mainly includes automatic throttle manifold system, backpressure pump system and remote automatic control center, and is capable of providing additional flow-rate and backpressure compensation required by constant pressure at hole bottom when making up connections, starting or shutting down the pump, changing the drilling fluid density and drill-string moving. The application of near-balanced and under-balanced controlled pressure drilling technology in Sichuan, Chongqing and Tarim regions show that under-balanced controlled pressure drilling technology can control the bottom pressure to be below the formation pore pressure, allowing gas to flow from the formation at a controlled rate, which helps protect and discover the reservoirs and is a viable technology with development potential.