The invention discloses an energy conservation optimizing method of a heat-engine plant ball mill pulverizing system based on sequential pattern mining, and the method comprises the following steps: carrying out a sequential pattern mining process on the on-site record data, so as to automatically obtain a mill load 1, the outlet temperature ot of the mill, the inlet negative pressure inp of the mill, the opening uh of a hot wind door, and sequential modes among circulation wind door opening ur, the mill output force pc, the mill load set value lsv, mill outlet temperature set value otsv and the mill inlet negative set value inpsv; and determining the best set values of the mill load, the mill outlet temperature and the mill inlet negative pressure at the current working condition on the basis of the current operation data and the obtained sequential mode by adopting a search method item by item, thus the energy conservation optimizing method is simple and feasible and has good commonality, and the pulverizing system can operate in a best manner on the premise of safety and stability, thus not only providing an effective guarantee for the excellent-quality burning of a boiler system, but also providing beneficial effects on a heat-engine plant.