Long-length steel billet cutting method

The invention provides a long-length steel billet cutting method. The long-length steel billet cutting method comprises the following steps: conducting original cutting design of a long-length steel billet in an MES system; measuring the actual length L2 of the long-length steel billet, subtracting the target length L1 from the actual length L2, and conducting calculation to obtain the deviation length X; when the deviation length X is larger than 0, abandoning the original cutting design, and correcting the cutting length of short-length steel billets according to the deviation length X and an original target cutting section number n; when the deviation length X is smaller than 0, if short-length steel billets which are subjected to non-fixed-length rolling exist in the n sections of short-length steel billets obtained by cutting the long-length steel billet, correcting the cutting length of each section of short-length steel billet which is subjected to non-fixed-length rolling; if the n sections of cut sho