The invention provides a spray-seeding revegetation method for riverbeds in a high elevation region, and relates to the technical field of sand prevention and fixation. The method comprises the stepsthat 1, construction is prepared in dry season of a river; 2, before spay-seeding construction, the construction region is prepared, the to-be-constructed region is leveled, and garbage is removed; 3,a sand-fixation substrate is spray-seeded, where in 15-40% by volume of deep clay soil, 20-35% by volume of humic acid, 0.1-2% by volume of pellet agent, 0.5-3.0% by volume of polymer binder, 30-45%by volume of wood meal, 5-10% by volume of distillers' grains, 3-5% by volume of organic fertilizer and 0.4-2.5% by volume of seeds are mixed to be uniform to be prepared into the sand fixation substrate, and the sand fixation substrate is put into a spray-seeding machine and sprayed out uniformly; 4, the spray-seeding thickness is 2-3 cm, and the spray-seeding thickness is uniform. Accordingly, the sand fixation substrate has the advantages of being resistant to long-time water erosion and periodical hydrodynamic force, high in capacity of resisting wind erosion, high in fixed capacity, highin vegetation survival rate, small in preservation difficulty and low in cost.