Abstract: Taking the arc serrated trailing edge blade as the research object and setting the triangular shaped serrated trailing edge blade and straight trailing edge blade as the reference group,the large eddy simulation combined with FW-H equation is used to compare and analyze the sound pressure level directivity and noise spectrum characteristics of three kinds of blades at different angles of attack. Through the analysis of the vortex structure around the three kinds of blades,the unique acoustic mechanism of the arc serrated trailing edge is further studied. The results show that,like the triangular sawtooth,the arc sawtooth structure does not change the dipole distribution of the sound pressure level directivity of the blade. The arc serrated trailing edge effectively reduces the noise in the middle and high frequency band,while the noise reduction effect in the low frequency band is not obvious. The sawtooth structure affects the development of the vortex at the trailing edge,which in turn affects the aerodynamic noise of the blade,and the influence of the arc serrated trailing edge on the trailing vortex structure is greater than that of the triangular shaped serrated trailing edge.