The invention discloses a multi-morphology rare earth doped BiVO4 composite photocatalyst and a preparation method thereof. The composite photocatalyst comprises the component of Ln(1-x)BiVO4, wherein Ln is equal to La, Ce, Pr, Nd, Sm, Gd, Dy, Er and Y, and x is equal to 0.01-0.3mol%. The photocatalyst disclosed by the invention has different morphologies and has the advantages of simple preparation technology, controllable morphology and crystalline phase structure of a target product and big specific surface area, and various organic pollutants, such as toxic and harmful phenols, aldehydes, and dyes, can be decomposed within a wider wavelength range.