A method for controlling thin pipeline steel cooling uniformity in an ultrafast cooling process belongs to the technical field of ultrafast cooling of steel plates. Pipeline steel is produced in batch by means of ultrafast high-strength uniform cooling, temperature uniformity of a steel pipe in the length direction is ensured by means of acceleration and head and tail shielding, the temperature difference between the head and the middle of the pipeline steel plate is about 20 DEG C after head and tail shielding, and the distance between a supercooling position and the head or the tail of the pipeline steel plate is shorter than 200mm. The longitudinal temperature uniformity of the steel pipe can be ensured, the temperature difference of the same steel plate is lower than 30 DEG C, and back-end cropping quantity is smaller than 200mm. By the aid of soft water sealing technology, ordered flow and control of accumulated water on the upper surface of the steel plate is ensured, the transverse temperature of the steel plate is uniform by means of reasonable cooling procedures, single-pass straightening batch production is finally realized, the straightening cost of the steel plate is reduced, and the integral performance of the steel plate is improved.