The present disclosure relates to the field of scientific drilling technology and provides a deep rock quality assurance coring device and coring method thereof. The deep rock quality assurance coring device comprises a drilling tool, a drilling bit, a central rod and a core storage body, wherein the drilling bit is mounted at the lower end of the drilling tool, the lower end of the central rod is connected to the core storage body, and the central rod is capable of driving the core storage body to move in the drilling tool in an axial direction of the drilling tool, a reservoir chamber having a lower end opening is arranged in the central rod, a core storage chamber having a lower end opening is arranged in the core storage body.