The theoretical,simulation,and experimental study on the spectrum Fourier analysis method(SFAM) to measure polarization mode dispersion(PMD)was pressented.With this method,the simulations for three PMD emulators were done,which were composed of one,two,three polarization maintain fiber(PMF) respectively.And the experimental measurements were done for a PMF,a 11 km-ling single mode fiber(SMF) and a commercial emulator.The difference of this method with previous one that counting the wavelength extrema is also studied.The result shows that the SFAM is more suitable to measure the PMD of strong coupling fiber,for the statistical characteristic of PMD has been considered.