The invention discloses a pull rivet resultant magnetization grouping flaw detection method and a pull rivet resultant magnetization grouping flaw detection device. The method comprises the following steps: (1) arranging a stepping conveying mechanism, arranging a broadband closed circumferential magnetic path consisting of opened magnet yokes, pull rivets and gaps and circumferential magnet exciting coils, arranging axial magnet exciting coils, providing two controllable alternative current generation resultant magnetic fields, arranging a manual screw nut screw rod lifting mechanism which is fixed at the opened magnetic yokes, and arranging a demagnetization conveying mechanism; (2) manually adjusting the vertical heights of the opened magnet yokes; (3) starting the conveying mechanism, magnetic suspension spraying devices, a magnetization power supply, ultraviolet radiation lamps and the demagnetization conveying mechanism; (4) conveying; (5) spraying the suspension; (6) resultantly magnetizing; (7) inspecting a product; and (8) demagnetizing. When the flaw is detected through controllable automatically conveyed pull rivets, the operation is carried out by multiple operators, 50 to 60 pull rivets can be accomplished within 1 minute, and the efficiency is improved by about 20 times when being compared with that of single pull rivet flaw detection. Through once resultant magnetization, various cracks and fine defects on the surface and near surface of a workpiece can be comprehensively checked at one time, the workpiece is magnetized in a non-contact mode, the magnet excitation capacity is low, the magnet yoke height can be adjusted, and the magnetization sensitivity in magnetizing rivets of different diameters is ensured.