The invention discloses cerium-lanthanum doped barium fluoride transparent ceramic and a preparation method thereof. Ce<3+> and La<3+> react with a barium fluoride matrix to obtain a substitutional solid solution, and the Cerium-lanthanum doped barium fluoride transparent ceramic is formed. The preparation method comprises synthesis of nanopowder and hot isostatic pressing sintering. Firstly, a hydrothermal method is adopted to synthesize the nanopowder which has grain size of 15-40 nm and has high dispersity. Then, hot isostatic pressing sintering is adopted to prepare the transparent barium fluoride ceramic with its density being greater than or equal to 99.5% and transmittance at visible and near-infrared band being greater than or equal to 80%. At 290 nm, there exists Ce<3+> characteristic absorption peak; and peak intensity and width are increased with increasing of Ce<3+> dosage concentration. The preparation method has the following advantages: material synthesis output is high; energy consumption is low; and operation is simple. The prepared barium fluoride transparent ceramic has excellent optical performance.