The present disclosure relates to a weld groove forming method and a hollow article. The weld groove forming method may include: (S110) determining whether a side end of a pipe may be processed into a form of a true circle by using a sensor robot; and (S220) forming a weld groove in a form of a true circle at the side end of the pipe by using an automatic beveling machine when the sensor robot determines that the side end of the pipe may be processed into a form of a true circle in the step (S110).