The magnetic yoke flaw detector has the characteristics of compact structure, reasonable layout, compact size, light weight and convenient carrying. It is suitable for the magnetic particle detection of surface and near surface defects of ferromagnetic materials in electric power, metallurgy, petrochemical, machinery and other industries, boilers, pressure vessels, pressure pipelines and various types of welded structures. The flaw detector can be directly connected to AC power, and can also be used with DC magnetized power supply, which is efficient and lightweight. Especially suitable for hull weld inspection, high-altitude steel structure weld inspection and pressure vessel internal operation.