The invention relates to a novel rectifying device and a rectifying method for an SCR (Selective Catalytic Reduction) denitrification device. The rectifying device serves as an important structure in an SCR denitrification reactor, is arranged above a catalyst, and is used for optimizing a flowing direction of flue gas flowing through the catalyst, reducing wear of the catalyst caused by flue gas deviation, and prolonging the service life of the catalyst. The novel rectifying device for the SCR denitrification device comprises a rectifying structure and a shielding structure (2), wherein the shielding structure is welded above the rectifying structure; a steel plate (4) is welded on the outer side of the rectifying structure; the shielding structure has an inverted-V-shaped structure.