Abstract: The circumference of the waved groove is in a form of a weakening sine wave.There are number of advantages resulted from the employment of the wave groove by the plug,mill,such as uniform deformation along with the whole circumference of the groove,easier of control the groove top screw-down,less groove-die wear,less frequency of jaming during rolling as well as better pipe wall thickness evenness.Also involved are the deformation theory, design,machining and operational performance of the waved groove.