The dynamics of h-BN hydrogenation depending on surface orientation of metals have not been elucidated. Here, we first demonstrate h-BN hydrogenation on Pt metal substrate via hydrogen plasma treatment. Pt metal is well-known as hydrogenation catalyst, promoting hydrogen adsorption on 2D materials and has strong interaction with 2D materials. To reveal phenomena of hydrogenation depending on surface orientation, we observe h-BN hydrogenation on various single-oriented Pt crystals by XPS. We analyzed extent of h-BN hydrogenation on various Pt single crystals, revealing catalytic activity of Pt inducing hydrogenation is related to difference of adsorption energy of hydrogen on Pt surface orientation. We propose hydrogenation proceeds from boron and then subsequent h-BN etching occurs simultaneously. Furthermore, we confirmed conversion of h-BN to graphene on Pt surface is affected by hydrogenation rate of h-BN.