The invention provides a sunlight pump laser amplifier suitable for amplification of multiple wavelengths, which includes an ytterbium-doped (Yb3+) optical fiber working substance, an optical fiber incidence port, an optical fiber emergence port, pumped sunlight and multi-wavelength seed laser. The ytterbium-doped (Yb3+) optical fiber working substance is arranged between the optical fiber incidence port and the optical fiber emergence port in a circular structure. The pumped sunlight is arranged at the optical fiber incidence port and located above the multi-wavelength seed laser. The ytterbium-doped (Yb3+) optical fiber working substance, the optical fiber incidence port, the optical fiber emergence port, the pumped sunlight and the multi-wavelength seed laser work together, so that themulti-wavelength seed laser can be amplified into multiple wavelengths. The amplifier of the invention can realize the simultaneous amplification of power of seed laser of multiple wavelengths, can beapplied to a wavelength division multiplexing satellite optical communication system, and can improve the space energy conversion efficiency and the space information transmission rate.