Polar Motion is generally considered to include five main periodic or non-periodic wobbles, which are secular wobble, Chandler wobble, annual wobble, sub-seasonal wobble and irregular wobble, respectively. As the geophysical fluid excitations within different frequency scale can lead to the different responses of Polar Motion, here a Fourier de-convolution transform method is used to extract, in frequency domain, the five main wobbles from Polar Motion. Then these specific wobbles are compared with their corresponding geophysical fluid excitations one by one. Our results show that annual wobble and its excitation have time variable amplitudes and phases, so their year to year comparison would be a good constrain in angular momentum domain by testing the simulated atmospheric, oceanic and hydrological angular momentum functions deduced from general circulation models. In addition, irregular wobble may detect the abnormal signals forced by global unusual meteorological events.