The invention discloses a manufacturing method for a waveguide amplifier with an erbium-doped tantalum oxide ridge structure. The amplifier made by the method comprises a substrate, a silica lower cladding, an erbium-doped lithium niobate film layer, a silica buffer layer, an erbium-doped tantalum oxide ridge waveguide structure, and a silica upper cladding. A silicon substrate lithium niobate film is used as a chip. The erbium-doped tantalum oxide whose refractive index is close to the refractive index of the lithium niobate is used as the ridge structure. In a communication band, through amplification effect of erbium ions, optical loss caused by processes of optical transmission and modulation can be made up. Compared with a dry etching technology, the manufactured ridge structure is low in process cost, and high in finished product rate, and stability of a device is improved. The manufacturing method is advantaged by simple manufacturing process, small device dimensions, small bending radius, and good stability.