The invention discloses a device and method for eliminating the welding stress of a steel pipe ring beam by mechanical vibration. The contact reliability problem of a vibration pickup and a structure member is solved by using a steel pipe ring beam vibration supporting seat and a vibration method, and a crystal tissue of a steel pipe ring beam welding joint is changed through the process of effectively transmitting the vibration wave energy of the vibration pickup to the structure member, thereby obtaining the purpose of weakening and eliminating the welding tress of the steel pipe ring beam structure member.