Abstract: Addressing deformation characteristics of the shell during rotary piercing operation, wall thickness unevenness is calculated by means of the FE simulation method. With a gage-measuring meter especially designed by the researchers, measurement of pierced shells by a specific steel mill was conducted on a batch basis. Then a comparison between the theoretic values and the measured values is made via FFT conversion, showing full compliance of the simulation values with the measured ones. It is therefore concluded that various technological parameters can be simulated to anticipate the unevenness of the shell wall thickness so as to set up the proper technological parameters as desired.