Abstract: In this paper,the main wok is studying the measur ement of grain size of 1Cr18Ni9TiA austentional stailess steel,GH132 and TG4 titaniumalloy,etc.Besides the conventional met allographical way,the measuring of the ultrasonic longitudinal wave velocity,ultrasonic attenuation and hardness of met al materials,the relations between these paramters and grain size is established. The results show that the tes is non-destructive and this way is feasible and applicable.