The utility model discloses a novel pressure control drilled well system which is composed of main devices such as a nitrogen making machine, a compressor, a supercharger, a mud pump, a pressure returning pump system, an automatic choke manifold, a choke manifold, a kill manifold, a blowout preventer unit and underground tools. According to the novel pressure control drilled well system, the function that nitrogen is filled is added on the basis of a common precise pressure control drilled well system, so that the functions of the common precise pressure control drilled well system are achieved, the lower limiting value of a mud density window is decreased, and the range of the mud density window is enlarged. When well leakage can not be stopped by means of common precise pressure control, the equivalent circulating density of a shaft is far lower than the density of water through the nitrogen filling method, and the condition of precise control of a shaft annular pressure section is reestablished. According to the novel pressure control drilled well system, the lower limiting value of the mud density window is decreased through the control over the discharging amount of nitrogen, the adjusting and control capacity is enhanced, the application range of a pressure control drilled well is enlarged, and the requirement for drilling is further satisfied.