A method for preparing the yttrium-doped barium fluoride scintillation crystal having a chemical composition of Ba (1-x) Y x F 2+x, wherein 0.01≤ x≤ 0.50, and the method comprises the steps of: weighing and mixing raw materials of YF 3 and BaF 2 according to the molar ratio BaF 2: YF 3 = (1-x): x to obtain a mixed powder, wherein 0.01 ≤ x ≤ 0.50; putting the mixed raw materials into crucibles in a vacuum furnace for thorough melting at a temperature of 1200 to 1400 °C, and then cooling the mixture to obtain Ba (1-x) Y x F 2-x polycrystalline material, or subjecting the mixed powder to isostatic pressing, and putting the resulting substance into crucibles and sintering it at 900 to 1200 °C in vacuum to obtain sintered Ba (1-x) Y x F 2+x polycrystalline material; and mixing the resulting polycrystalline material with an appropriate amount of PbF 2 powder, which is act as a deoxidizer, and growing crystals by vertical Bridgman method; wherein the processes of the vertical Bridgman method include: maintaining the furnace in a vacuum degree of less than 10 -3 Pa, melting the Ba (1-x) Y x F 2+x polycrystalline material and PbF 2 powder at 1200 to 1400 °C, subjecting the resulting melt to crystal growth wherein the descending speed of the crucible is 0.5 to 4 mm/hour, and cooling the grown crystal to room temperature at a temperature decreasing rate of 10 to 50 °C/hour; wherein the deoxidizer PbF 2 is added in an amount of 0.5 to 5 wt% of the Ba (1-x) Y x F 2+x polycrystalline material. weighing and mixing raw materials of YF 3 and BaF 2 according to the molar ratio BaF 2: YF 3 = (1-x): x to obtain a mixed powder, wherein 0.01 ≤ x ≤ 0.50; putting the mixed raw materials into crucibles in a vacuum furnace for thorough melting at a temperature of 1200 to 1400 °C, and then cooling the mixture to obtain Ba (1-x) Y x F 2-x polycrystalline material, or subjecting the mixed powder to isostatic pressing, and putting the resulting substance into crucibles and sintering it at 900 to 1200 °C in vacuum to obtain sintered Ba (1-x) Y x F 2+x polycrystalline material; and mixing the resulting polycrystalline material with an appropriate amount of PbF 2 powder, which is act as a deoxidizer, and growing crystals by vertical Bridgman method; wherein the processes of the vertical Bridgman method include: maintaining the furnace in a vacuum degree of less than 10 -3 Pa, melting the Ba (1-x) Y x F 2+x polycrystalline material and PbF 2 powder at 1200 to 1400 °C, subjecting the resulting melt to crystal growth wherein the descending speed of the crucible is 0.5 to 4 mm/hour, and cooling the grown crystal to room temperature at a temperature decreasing rate of 10 to 50 °C/hour; wherein the deoxidizer PbF 2 is added in an amount of 0.5 to 5 wt% of the Ba (1-x) Y x F 2+x polycrystalline material. maintaining the furnace in a vacuum degree of less than 10 -3 Pa, melting the Ba (1-x) Y x F 2+x polycrystalline material and PbF 2 powder at 1200 to 1400 °C, subjecting the resulting melt to crystal growth wherein the descending speed of the crucible is 0.5 to 4 mm/hour, and cooling the grown crystal to room temperature at a temperature decreasing rate of 10 to 50 °C/hour; wherein the deoxidizer PbF 2 is added in an amount of 0.5 to 5 wt% of the Ba (1-x) Y x F 2+x polycrystalline material.