Abstract: Based on the first principles, the surface characteristics of vertical heterojunction composed of single-layer molybdenum disulfide (MoS₂) on 1-7-layer hexagonal boron nitride (hBN) substrates and the capacitance voltage characteristics of MIS (metal insulator semiconductor) structure are calculated and analyzed by first principles. Based on the analysis of the influence of hBN layer number on MoS₂ dielectric constant, the influence of hBN layer number on MoS₂/hBN interface surface state is further studied. Finally, the influence of hBN layer number on MIS structure is calculated. The calculation results show that the properties of MoS₂FET fabricated by MoS₂/hBN heterostructure can be adjusted by changing the number of two-dimensional hBN layers, which provides necessary theoretical support for the development of new generation MoS₂ based nano devices.