A dynamic straightening method for a left/right tilt. The method includes: drawing an unevenness curve according to a distance from a shapemeter to a surface of a plate, where there are a plurality of unevenness curves; using a barycentric formula to obtain a first barycentric coordinate of each unevenness curve; calculating a tilt value of a straightening roll corresponding to each unevenness curve according to the first barycentric coordinate of each unevenness curve; determining an unevenness curve of a current straightening roll; adjusting the straightening roll according to the tilt value of the straightening roll corresponding to the unevenness curve, to straighten the plate; and going back to the step of determining an unevenness curve of a current straightening roll until the plate is totally straightened. Such method improves plate straightening accuracy by dynamically adjusting parameters of the straightening roll.