In the process of magnetic flux leakage (MFL) testing, the leakage magnetic field decreases as the testing velocity increases, which leads to the severe detection omission. To address this issue, factors affecting high-speed magnetic flux leakage testing are analyzed, multistage magnetization structure is then proposed. By comparing magnetic flux leakage signals characteristics on the surface of steel pipe with high speed and low speed, effectiveness and feasibility of multistage magnetization structure are analyzed. Results show that multistage magnetization structure can effectively extend magnetization time. Compared with single magnetization, the magnetic flux leakage signal of the inner wall of the steel pipe can be detected effectively with multistage magnetization structure at high speed, and the magnetic flux leakage testing precision is improved.