A pressure measuring method, applied to a pressure measuring apparatus, comprising: measuring a first pressure sensing value of the pressure measuring apparatus, which corresponds to a first pressure in a test mode; measuring a second pressure sensing value of the pressure measuring apparatus, which corresponds to a second pressure in the test mode; generating a first corresponding function according to the first pressure, the second pressure, the first pressure sensing value and the second pressure sensing value; sensing a third pressure sensing value via the pressure measuring apparatus in a normal mode; and generating a third pressure according to the third pressure sensing value via the first corresponding function; wherein the pressure measuring apparatus operates at a first scan frequency. By this way, the pressure sensing value can be calibrated, to solve the issue that the pressure sensing values are affected by scan frequencies.