The decoloration of the erythromycin broth by the polypropylene anion exchange fiber is studied in this paper, including the effects of contact time and pH value on decoloration characteristics. The results show that the polypropylene anion exchange fiber is better than the ion-exchange resin, with advantages such as higher exchange and rebirth speed. When the ambient temperature is 301K, the decoloration is fast, and the decoloration rate reaches 85.3% in 30 minutes, and the lose rate of erythromycin is 1.17% in a static test. The potency and the quality of the erythromycin product are improved through the dynamic decoloration by the ion-exchange fiber.