The interface microstructure and su perhardness effect of W/Mo nano -mul tilayers have been studied.The W/Mo multilayers were synthesized with magnetron sputtering technique and their microstructure and hardness were characterized by XRD,TEM,HREM,and mi-croindenter,respectively.The results show that the W/Mo multilayers h ave a epitaxially grown mode and got polycrystal superlattices.With the decrease of modulation period of multilayers,the interplanar dista nces of Wand Mo layers are close to eac h other resulting from coherent strain on the interface,which produces an alternating stress field and s trengthens multilayers.