Objective To investigate the clinical effects of the maxillary molar distalization with modified Distal- Jet appliance. Methods 15 patients(average age 12.3 year- old)with maxillary molars shifting mesially were selected as the subjects. Maxillary molars of all patients were distalized with modified Distal- Jet appliance. Results All patients achieved good occlusion, normal overjet and overbite with modified Distal- Jet appliance. Conclusion Modified Distal-Jet appliance can distalize maxillary molars effectively.