The invention discloses borosilicate glass/h-BN complex-phase ceramics and a preparation method therefor and belongs to the technical field of preparation of ceramics. The method comprises the steps: preparing 50-80% (by mass) of silica, 10-30% (by mass) of boron oxide and 5-20% (by mass) of sodium oxide, and then, adding 0-30wt% of h-BN into silica, boron oxide and sodium oxide; carrying out mixing so as to obtain mixed powder, putting the mixed powder into a baking oven for drying, and then, carrying out granulating; and carrying out preprssing on the obtained powder so as to obtain green wares, then, carrying out cold isostatic pressing treatment, then, putting the green wares in an air furnace for degumming so as to prepare a molded body, putting the molded body in a sintering furnace, vacuumizing the sintering furnace or introducing a certain protective atmosphere into the sintering furnace, heating the sintering furnace to the temperature of 700-1,200 DEG C, and carrying out heat preservation for 1-5 hours, a borosilicate glass/h-BN complex-phase ceramic sintered body. According to the method, the in-situ nanocrystallization of h-BN is realized by using a shearing force generated from a glass phase and the in-situ stripping effect of the shearing force, so that a preparation method for boron nitride nano complex-phase ceramics is optimized. The prepared boron nitride nano complex-phase ceramics can be extensively applied to military engineering sciences and technologies and industrial production such as metallurgy, chemical engineering, machinery, electronics, atomic energy and space navigation.