Abstract: In order to further lower the measurement limit of vacuum partial pressure and address issues such as the periodic calibration of traditional vacuum measurement instruments, photonic quantum technology has been adopted for the measurement and calibration of vacuum partial pressure. This method, based on cavity ring-down spectroscopy (CRDS), enables high-precision measurement of gas absorption coefficients. By applying relevant formulas, the molecular number density of the gas is retrieved, thereby obtaining the corresponding vacuum partial pressure value. This paper systematically reviews the emergence and development of CRDS technology, highlighting its unique advantages in the field of vacuum partial pressure, including non-invasiveness, high sensitivity, and calibration-free operation. Through the development of a typical ultra-low vacuum partial pressure calibration device at the Lanzhou Institute of Physics, combined with relevant simulation results, the feasibility of CRDS technology for ultra-low vacuum partial pressure measurement is theoretically validated. The final analysis indicates that CRDS technology holds promise for achieving even lower pressure measurements in the future, advancing vacuum metrology toward portability and absolute standardization.