We use interface engineering technology to obtain high interface quality of extreme ultraviolet (EUV) multilayer. By inserting ultrathin (<0.5 nm) B4C layer between Mo and Si layers in Mo/Si multilayer, the interdiffusion in the multilayer is decreased obviously and the reflectivity can be estimated to increase by 2%. By inserting a new inert material barrer between Mo and Si layers, the thermal stability of new forming Mo/X/Si/X multilayer is increased significantly. The multilayer is annealed at 500 oC for 100 h with the fluctuation of period thickness smaller than 0.1 nm, and the high resolution transmission electron microscopy image also shows that the mirostructure of the multilayer is not changed obviously.