The invention discloses a preparation method of vonoprazan fumarate. The preparation method includes: S1, dissolving 5-(2-fluorophenyl)-1H-pyrrole-3-carboxaldehyde (I) in organic solvent, mixing with methylamine alcohol solution for 6-8h to generate imine, reducing with metal borohydride for 1-2h, and performing post-treatment to obtain a compound according to a formula II; S2, dissolving the compound prepared in the step S1 according to the formula II, in organic solvent, performing ice bathing and mixing with Boc anhydride to allow reaction for 1-2h, and performing post-treatment to obtain a compound according to a formula III; S3, dissolving the compound prepared in the step S2 according to the formula III, in organic solvent, adding sodium hydride and crown ether, adding 3-pyridine sulfuryl chloride, mixing for reaction for 1-2h, and performing post-treatment to obtain a compound according to a formula IV; S4, reacting the compound prepared in the step S3 according to the formula IV, in trifluoroacetic acid and methylene dichloride solution to obtain a compound according to a formula V; and S5, dissolving the compound prepared in the step S4 according to the formula V, in organic solvent to be salified with fumaric acid, thereby obtaining the vonoprazan fumarate (VI). The preparation method has few side reactions and high intermediate purity and allows simple post-treatment.