In order to improve the recovery efficiency of iron minerals in specularite tailings，a new process of ultrasonic pretreatment combined with polymer flocculation and magnetic separation is proposed. The effects of ultrasonic dispersion treatment time and the dosage of polyacrylamide ( PAM) ，pregelatinized potato starch ( PPS) and pregelatinized cassava starch ( PCS ) on the sorting index of specularite tailings are discussed. Combined with metallographic microscopy observation and infrared spectroscopy ( FTIR) analysis，the mechanism of the agent-mineral interface is revealed. The results show that all three flocculants could effectively improve the recovery of specularite tailings，and PPS has the best effect. Under the best test conditions ( ultrasonic dispersion treatment for 30 s，PPS dosage of 10 g /t，slurry pH = 10. 0， magnetic field strength of 0. 5 T) ，magnetic separation concentrate with iron grade of 42. 53% and recovery rate of 63. 10% can be obtained，and the iron recovery rate is increased by 10. 66% compared with the conventional high-gradient magnetic separation process. Mechanistic studies show that PPS and PCS are mainly chemisonded with the surface of pyroxene through hydroxyl and carboxyl functional groups to form stable complexes. However，the selectivity between PAM and eperolite is mainly through the chemical coordination and physical crosslinking between amide groups and Fe ^{3 +} ，and its selectivity for fine-grained iron minerals is lower than that of starch flocculants.