Abstract: During the dynamic frequency obtaining process of the blade on the axial-flow type ventilator, due to the shortage sampling and inhomogeneous samplin g features of the sampling data by the timer sensors on the two blade tips, thus the blade dynamic frequency would not be obtained with the simple Fourier variation.Th erefore with the zero inserted in the sampling data and the re-sampling, the Fourier variation property could be applied to obtain the difference frequency and the metho d of the blade dynamic frequency could be obtained.In order to improve the feasibility of the method applied to the vibration measurement of the axial flow type ventilato r, according to a mode of the ventilator, a software was applied to simulate the vibration signals of the blade. The method was applied to treat the inhomogeneous sampl ing data. The relative error of the two blade dynamic frequency was 0.05% and 0.012% individually.Thus the method was feasible to the vibration measurement of the ax ial flow type ventilator.