Children wake up with one eye swollen, may be physiological factors, mosquito bites, allergies and other factors. 1. Physiological factors: when the child sleeps in an incorrect sleeping position, resulting in one side of the eye is compressed, resulting in poor blood circulation, waking up one eye will be found swollen. 2. Mosquito bites: more indoor mosquitoes may bite the eyelid area of the child, after the bite, it will lead to swelling of one eye, which may also be accompanied by itching, redness and other symptoms. 3. Allergy: one side of the eye in contact with allergy-prone substances, so that one side of the eye allergy, will cause localized edema of the eye, accompanied by itching and other symptoms. Children wake up with one eye swollen, may also be caused by other reasons, the symptoms have not been reduced or there are other abnormal symptoms, it is recommended to consult a doctor to avoid delaying the condition.