In the present study, we report the synthesis of selective magnetite molecular imprinted polymer (Fe3O4@SiO2@NH2-Que-MIP) for the first time by a simple ultrasonic mediated co-precipitation polymerization route and applied as a sorbent for selective extraction of quercetin from onion samples. The ultrasonic energy is not only a green source of energy but also reduces the polymerization reaction time 5 folds as compared to the conventional route. The surface morphology and functionality of the prepared polymeric sorbent was characterized by SEM and FT-IR. The adsorption mechanistic pattern was best defined by Langmuir and the pseudo-second-order kinetic. Different influencing parameters on the quercetin rebinding such as pH, dose, contact time, the concentration of an analyte, and temperature were optimized to get maximum adsorption capacity. The regeneration study of the polymeric sorbent was also carried out. A good linear concentration range of (0.32-25) mu g/mL was attained. The LOQ and LOD were 0.20 and 0.06 mu g/mL respectively. The method validation and analytical performances were obtained for the developed polymeric sorbent by spiking with quercetin in onion samples, and the results were found in good agreement with the spiking value. The developed polymeric sorbent was applied successfully for the selective extraction of quercetin from real samples.