The invention discloses a multi-wavelength DFB (distributed feedback) semiconductor laser array and a preparation method. The multi-wavelength DFB semiconductor laser array comprises gratings, waveguides and output optical cavity surfaces, wherein the gratings are lateral-coupled surface gratings, the waveguides are ridge waveguides, and the cavity surfaces are formed by etching. The multi-wavelength DFB semiconductor laser array can effectively suppress interference of FP (fabry perot) longitudinal modes, and has the advantages of simple preparation method, low cost, wide applicability and accurate wavelength control.