The invention discloses a capillary isoelectric focusing method used for rapid determination of content of each ingredient of a protein mixture. The capillary isoelectric focusing method comprises following steps: 1) an amphoteric carrier, an additive, an isoelectric point marker, and a protein mixed sample to be analyzed are mixed so as to obtain a mixed solution; 2) loading of a capillary column with the mixed solution is carried out, and focusing and detection are performed so as to obtain an isoelectric focusing spectrum; 3) the isoelectric focusing spectrum obtained in step 2) is compared with isoelectric focusing spectrums of single protein ingredients of the protein mixed sample to be analyzed so as to determine single protein ingredients corresponding to different isoelectric point ranges in the isoelectric focusing spectrum obtained in step 2); and 4) based on intercomparison results obtained in step 3) and isoelectric focusing spectrum information obtained in step 2), the content of each ingredient of the protein mixed sample to be analyzed is determined. The capillary isoelectric focusing method is high in universality; analysis period is short; and data processing is simple; so that the capillary isoelectric focusing method is suitable to be applied for production technology exploitation and quality control of protein mixtures.