The invention discloses a sampled data processing method combining PMU dynamic data processing. Under the condition that deviation happens to system frequency, the method can effectively restrain the influence of the frequency deviation in different function applications. After the frequency of an electric power system is deviated from rated frequency, original sampled data are dynamically processed according to a PMU high-precision frequency calculation result to meet the application requirements for harmonic component calculation of each time, difference-frequency system synchronous switching-on and the like. Meanwhile, the defects that conventional sampling achieves the digitization of multi-measuring-point input analog amount on the same ADC, only one main channel can be selected in frequency tracking to be executed, and then the calculation errors of other measuring points are possibly amplified are overcome. The sampled data processing method improves the measurement precision and control reliability of a measurement and control device after the frequency of the electric power system is deviated.