In this paper, a new method of basic oxygen furnace (BOF) slag component modification with a regulator was studied. The main mineral was designed as C₄AF, C₂S and C₃S in modified BOF slag, and the batching method, mineral compositions, hydration rate, activation index and capability of resisting sulfate corrode also were studied. XRD, BEI and EDS were used to characterize the mineral formation, and SEM was used to study the morphology of hydration products. The results show that most inert phase in BOF slag can be converted into active minerals of C₄AF and C₂S through reasonable batching calculation and the amount of regulating agent. The formation of C₄AF and C₂S in modified BOF slag is better, and a small amount of MgO is embedded in the white intermediate phase, but C₃S is not detected. With the increase in the CaO/SiO₂ ratio in raw materials, the CaO/SiO₂ ratio of calcium silicate minerals in modified BOF slag increases, the contents of f-CaO are less than 1.0%, and the activity index improves. Compared with the BOF slag, the activity index and exothermic rate of modified BOF slag improved obviously, and the activity index of 90 days is close to 100%. With the increase in modified BOF slag B cement, the flexural strength decrease; however, the capability of resisting sulfate corrode is improved due to the constant formation of a short rod-like shape ettringite in Na₂SO₄ solution and the improvement of the structure densification of the hydration products.