The present invention discloses a method for preparing manganese-doped perovskite quantum dots capable of emitting high-brightness white light, wherein the manganese-doped perovskite quantum dots are Mn:CsPb2(Br/Cl)5. The preparation method comprises: (1) respectively dissolving PbBr2, CH3(CH2)5NH3Br, MnCl2.4H2O and CsBr in N,N-dimethylformamide (DMF) to prepare a reactant precursor solution; and (2) sequentially transferring the precursor solution into stirred toluene to form the quantum dot material, wherein the transferring method is adding at a rate of 20-60 drops/min in a dropwise manner. According to the present invention, the Mn doping can be controlled and induced without the complex thermodynamic process, the method has advantages of mild reaction condition, simple process and convenient operation, the precursor solution has good stability and can be used repeatedly a plurality of times, and the method is suitable for industrial promotion.