The invention provides a high precision pressure acquisition method and system. The method comprises the steps that: when a differential circuit is used for calculating differential pressure, coupled ripple waves of acquired signals are processed to obtain a differential pressure value; the differential pressure value is subjected to digital filtering for eliminating abnormal out-of-range signal; the filtered differential pressure value serves as the final result. The high precision pressure acquisition method and system solve the problem of pressure acquisition precision by processing ripple through a differential circuit and a digital filtering algorithm thereby improving the pressure acquisition precision, and further obtaining high precision acquired data and more accurate differential pressure test results in a lost-cost and simple manner.