The invention discloses a negative-pressure uniform coating crossed yoke method magnetic powder detection crawling device. The negative-pressure uniform coating crossed yoke method magnetic powder detection crawling device structurally comprises an outer expanding shell, a light supplementing lamp, a crossed yoke type magnetic powder flaw detector, a machine frame, a movable wheel, a liquid spraying kettle, a negative pressure ring, a magnetic plate placing column and a driving motor. The negative pressure ring is provided, so that when magnetic suspension is sprayed to the surface of the magnetic powder, absorbing forces generated by a left absorbing ring and a right absorbing ring at the two ends can absorb the magnetic suspension towards two sides and the dispersing speed of the magnetic suspension can follow the moving speed of the device; furthermore, small air holes in a left adsorbing plate at the left end are dense, an air net is provided and negative pressure machines at the two ends can control output voltage, so that the adsorbing force generated at the left end is large, the dispersing speed of the magnetic suspension towards the left end can follow the displacement difference of the two ends, the magnetic suspension covers the magnetic powder uniformly, and the image tracked by the crossed yoke type magnetic powder flaw detector is more comprehensive.