Abstract: The performance of hexagonal boron nitride and graphene heterojunctions (hBN/Graphene) as anode materials for lithium–ion batteries is systematically studied using first–principles methods. The most stable heterojunction stacking structure is identified based on maximum binding energy. Lithium adsorption energies are calculated at high–symmetry sites on the outer surfaces of both materials and at the interlayer interface. Density of states calculations shows a non–zero density at the Fermi level for both pristine and lithium–adsorbed heterojunctions, indicating good electrical conductivity. Calculate the diffusion barrier of lithium atoms between different adsorption sites by LST-QST method, and calculate the open-circuit voltage and theoretical specific capacity as lithium atoms sequuentially layer by layer. With three lithium layers adsorbed, the open–circuit voltage is 1.18 V and the theoretical specific capacity is 1154 mAh·g^–1, demonstrating great potential for high theoretical capacity. These findings indicate that hBN/Graphene heterojunctions are promising candidates for high–performance lithium–ion battery anodes.