As a main component of waste electrical and electronic equipment (WEEE) plastics, polycarbonate (PC) shows an important recycling significance. However, separating PC from WEEE plastics is difficult due to their similar hydrophobic surfaces and densities. Herein, a novel surface modification method using Fenton treatment combined with ultrasonic was proposed to selectively separate PC from acrylonitrile–butadiene–styrene (ABS) and polyvinylchloride (PVC) by froth flotation. The effects of surface modification and flotation conditions on the flotation recovery of plastics were investigated to determine the optimum separation conditions for PC. The optimum conditions are ultrasonic power 240 W, ultrasonic time 8 min, molar ratio (H 2 O 2 /Fe 2+ ) 100, hydrogen peroxide concentration 0.3 mol/L, pH 3, frother concentration 20 mg/L, stirring rate 1800 rpm and flotation time 4 min. Under optimum conditions, the recovery and purity of PC with different mass ratios exceed 97.97% and 99.18%, respectively. Contact angle and Fourier transform infrared spectroscopy were used to ascertain the mechanism of surface modification. The surface of PC becomes more hydrophilic due to the introduction of oxygen-containing groups induced by surface modification. Consequently, this study provides a practical surface modification method for the separation of PC from WEEE plastics, which will effectively promote the recycling of PC.