BN based composites were prepared by hot-pressing using h-BN as main material in ceramic preparation process. The bulk density, bending strength, vickers’ hardness, thermal expansion coefficient, phase composition and microstructure were tested and analyzed by using modern testing technology. The results indicate that the best formula is H1, the bulk density is 2.77 g.cm-3, the bending strength is 231.07MPa,the hardness is HV5 182.73, the thermal expansion coefficient is 6.75×10-6℃-1 at 1400℃. XRD phase composition analysis showed that the main crystal phase of the sample is magnesium aluminium spinel and boron nitride. SEM and EPMA microstructure and element analysis showed that the porosity apertures diameters are under 3μm, the phase distribution are uniformly as well.