Large eddy simulation and acoustic analogy were performed to investigate the effect of trailing edge serrations on the turbine cascade noise. Two different trailing edge were designed. Comparisons were made for the sound power of two different serrated trailing edge cascades and straight trailing edge cascade under Re=3.3×105 (based on the blade chord and cascade outlet velocity).The result shows that the trailing edge serrations can reduce the blade suction surface boundary layer's separation noise by about 5dB and the trailing edge vortex shedding noise by about 10dB. Further investigation shows that trailing edge can reduce blade surface pressure fluctuation amplitude by about 50% near the trailing edge and change the vortexes of large spanwise correlation length into those of smaller spanwise correlation length. Furthermore

the trailing edge serrations can eliminate the trailing edge vortex shedding. The above three factors work jointly and contribute to the final noise reduction.