Children’s lower eyelid blue may be related to periorbital hyperpigmentation, trauma, circulatory diseases and other reasons. 1. Periorbital hyperpigmentation: commonly known as “dark circles”, such as long-term sleep deprivation and other excessive fatigue can lead to poor blood circulation in the eyes, the phenomenon of lower eyelid greening. 2. Trauma: If the child’s lower eyelid is hit by trauma, it can cause localized bruising, which is manifested as a bluish lower eyelid. 3. Circulatory system diseases: such as congenital cyanotic heart disease, due to the decrease of blood oxygen saturation, the phenomenon of the lower eyelids may appear. Parents are advised to take their children to the hospital in time to clarify the cause, and if treatment is needed, standardized treatment should be carried out under the guidance of the doctor, so as not to bring adverse effects to the body due to the delayed condition.