The invention provides a prefabricated prestressed concrete anchorage pier for slope strengthening and manufacturing and construction methods thereof. The prefabricated prestressed concrete anchoragepier comprises a prestressed concrete anchorage pier unit provided with a cross beam and a longitudinal beam which are crossed into a cross shape, concrete ribs located on the periphery of the prestressed concrete anchorage pier unit, and an anchorage head part located at the crossed position of the cross beam and the longitudinal beam; and prestressed reinforcements are arranged in the cross beamand the longitudinal beam. The prefabricated prestressed concrete anchorage pier adopts prestressed concrete lattice beams, the section property of the beams can be improved, larger anchorage force is borne, and the defect that when traditional cast-in-place reinforced concrete lattice beams are under large anchor cable anchorage force, the midspan positions of the reinforced concrete lattice beams can be pulled cracked possibly, and consequently the rigidity of components is lowered is overcome; and according to the prefabricated prestressed concrete anchorage pier, a manufacturing process can further be simplified, mounting is convenient, adjusting is easy during mounting, the construction period is shortened, and the construction cost is saved.