Abstract: This paper presents the comparison of the leading edge separation flow without and with the excitation of select frequency.A variety of excitation effects on the separation flowfield are revealed as(1)delaying separation flow or decreasing separation flow area,(2)modifying turbulence structure,intensifying turbulent activity and enhancing growth rate of separated shear layer,(3)enhancing backflow activity of local region,(4)promoting reattachment and changing separation patterns and vortex distribution,(5)weakening turbulence fluctuation of wake flow,and(6)increasing inclination of wake flow.