Purification method for removing homodimers in bispecific antibody

The invention provides a purification method for removing homodimers in a bispecific antibody. The purification method comprises the following steps: sequentially carrying out mixed mode chromatography and anion exchange chromatography on a supernatant culture solution for expressing the bispecific antibody to obtain the purified bispecific antibody, the mixed mode chromatography is chromatography performed by using a filler capable of simultaneously performing hydrophobic interaction and electrostatic interaction; the bispecific antibody comprises a bispecific antibody of which the antibody structure is Knob-In-Hole. According to the present invention, the bispecific antibody is purified by using the mixed mode chromatography and the anion exchange chromatography, such that the impurities such as the homodimers in the bispecific antibody are efficiently removed through the mixed mode chromatography, i.e. The chromatography using the hydrophobic interaction and the electrostatic interaction, and then the puri