Abstract: A new degree of freedom for turbomachinery design Edge Matching (EM) technique is presented in this paper.The so called EM is named from spatial relationship (more precisely,phase angle relationship) between trailing edge and leading edge curves of two neighboring blade rows.In fact,the blade trailing edge denotes the profile of outflow,in which the wake,the shock wave and other secondary flow phenomena are involved,while the blade leading edge presents potential interference on the former blade.When the steady flow design method is used,these effects related to the blade edges are considered partly.This means that the relative position between neighboring edges only has little influences on the turbomachinery performance.However,in the frame of unsteady flow this influence is evident and great.The theoretical analysis about EM technique is introduced first.The potential usage of EM technique is clearly pointed out.Then unsteady simulations about a turbine cascade and a linear cascade are conducted.The results show that the EM technique may be widely used in improving the aerodynamic,aeroelastic,aeroacoustic and heat transfer performance of turbomachinery.It is believed that the EM technique will advance the unsteady design of turbomachinery.