Abstract: Two-dimensional NbSe₂ material has attracted significant interest for unique electronic structure and physical properties. However,few-layer NbSe₂ crystal is always chemically unstable in air, which severely degrades the perform ance of devices.Here we report a remedial approach based on eleavage,transfer,alignment and encapsulation of air-sensitive two-dimensional crystals,all inside a controlled inert atmosphere.We prepared bilayer NbSe₂ devices passivated with h-BN few-layer by using the standard micro-nano processing technology,with graphene as one-dimensional electrical contact.The resuhs show that the device exhibits robust superconductivities with transition temperature about 6.8 K and charge-density-wave phase change happens in ~32 K. Its critical current density of superconductivity is approximately 30 mA/μm² at 2 K and critical magnetic field is beyond 3 T at 2 K.In addition,device performance of hetero-structure does not obviously degrade after storage in air for several months.