Abstract: In order to investigate the influences of unsteady aerodynamic excitations imposed on the blade, we focused on analyzing three atypical coherence functions between unsteady aerodynamic excitations and responses. By using the data obtained from single-stage low-speed axial compressor test rig and with coherence and partial coherence methods, we investigated the characteristics of three kinds of excitations and analyzed the coherence between excitation component and response signal. Our results indicated that coherence method could extract the response characteristics of the unsteady aerodynamic excitations and distinguish different influences on the blade. And with this method, we could conduct the quantitative analysis and ordering of each excitation component; rail excitation’s influence on the blade concentrates in the higher frequencies, rotating stall’ aerodynamic excitation concentrates in the low frequencies and the inlet distortion exists in both high and low frequencies. At the same time, we could use the partial coherence analysis to compare the characteristics of individual aerodynamic excitation and extract various factors existing in the mixed excitations, additionally, we could conduct quantitative analysis of each excitation’s influence on the response when a variety of unsteady aerodynamic excitations coexisted.