The invention relates to a single-throttling-channel pressure control drilling method and a single-throttling-channel pressure control drilling device suitable for high-flow change, and is applied to the field of well tube pressure and flow control during petroleum and natural gas drilling. The device consists of a vertical pipe measurement system, a back pressure compensation manifold and flow measurement system, a connection manifold, an automatic throttling manifold, a wellhead return flow measurement system and a signal acquisition and logic control system. The device can precisely measure the pressure at the bottom of a well, the vertical pressure at a wellhead, the sleeving pressure and pump-in and returning flow of drilling fluid; furthermore, due to the analysis of the logic control system, a working condition of the bottom of the well is judged, and a closed-loop control or block experience mode is selected according to the working condition, so that the back pressure applied by the throttling manifold to the wellhead is automatically adjusted in real time, and perfect well shaft pressure control is implemented; therefore the complicated underground problems of a narrow density window, spraying and leakage coexistence and the like are effectively solved.