Abstract: Asynchronous motor adopted with vari-frequency adjustable speed bas shown great superiority. In the technical renovation project of the Tieling-Dalian Oil Pipeline, we imported and adopted STMORVERT A type AC vari-frequency adjustable speed motors made in Cermany. The paper introduces the basiC property and working principle of such motor. At the same time, a good economic-efficieney has been achieved. This will provide reference for the technical renovation and research of cross country oil pipeline in the future.