Abstract: It is very important to accurately calculate the first harmonic of the frequency and amplitude in the detection of tire uniformity. There is a very big error between the calculated data based on traditional fast Fourier transforms (FFT) and actual data if it is non-integer-period sampling. A dressing method of non-integer-period sampling data based on sinc function was proposed in this paper. Based on the application of FFT, to construct standardized sinc function, the actual frequency and the corresponding peak of the measured data can be obtained by using the data of FFT. Accurate data can be obtained by applying the method. To a certain extent, it can make up for the deficiencies of the application of FFT when using the integer-period sampling. It has been successfully used in tire uniformity testing systems.