Abstract: Existing cold atom ultra-high vacuum (UHV) and extreme high vacuum (XHV) experimental measurements and theoretical research are mostly focused on a single gas environment, and there is little systematic research on the partial pressure of multi-component mixed gases. The collisional loss of cold atoms is influenced by factors such as atomic species, temperature, and gas types, with different gases causing varying degrees of cold atom loss under the same testing conditions. Theoretically, this difference can be utilized for partial pressure measurements. It is expected to compensate for the deficiencies in sensitivity, accuracy, and other performance aspects of vacuum mass spectrometers in the precise measurement of ultra-high/extra-high vacuum environments. This paper first proposes a theoretical hypothesis and experimental method for calculating the partial pressures of mixed gases based on the gas-specific differences in cold atom collisional loss rates. Subsequently, the partial pressures of an H₂-He gas mixture were calculated using the loss of ⁷Li cold atoms trapped in a magneto-optical trap, and these values were compared with the partial pressure measured by the vacuum mass spectrometer, where the relative deviation of the He partial pressure measurement was the largest, at 34.4%. Then the uncertainty of pressure measurement was analyzed, and it was found that the reason for the large relative deviation may be the incompleteness of measurement theory and experimental measurement system. Finally, the limitations of the partial pressure measurement method based on cold atoms and the direction of future research were discussed.