The invention discloses a preparation method of fiber-reinforced curved-surface friction material to solve the technical problem that a preparation method of existing curved-surface friction material is complex. According to the technical scheme, the method comprises: dry mixing staple fiber, a binder, a friction performance regulator and a filler, adding a binder solution for kneading, adding the kneaded semi-dry material into an extrusion device, thin-passing to obtain thin material, blanking the thin material to obtain friction material preform in required shape, winding, naturally drying, and thermally treating in a drying box to obtain the fiber-reinforced curved-surface friction material. In the preparation method, the simultaneous use of the solid binder and the liquid binder imparts good softness to the friction material preform, the addition of the staple fiber improves toughness of the friction material preform, and therefore, the preform may be wound according to surface radian of the friction material in the required shape to finally obtain the curved-surface friction material, the preparation process requires no mold forming with a mold, and the method is simple.