The hug reflex is also known as the startle reflex, which can be caused by hitting the mattress on both sides of the child’s head. It is best to drag the child’s head and back with your hands, so that the child is lying in a sloping position, with the trunk at an angle of 30 degrees to the bed, and then quickly make his head tilt backward by 10-15 degrees and drag the upper and lower limbs to abduct, while the trunk and fingers are straightened, and then the upper limbs are flexed to present a hug. The hug reflex is an inherent reflex of the spinal cord and belongs to the unconditioned reflex. If the hug reflex is lacking, it means that the child’s neurological system is not mature, and the second may be due to damage or lesion of the neurological system, intracranial hemorrhage or other intracranial diseases. The reflex will gradually disappear with the development of the higher centers of the cerebral cortex. This reflex is obvious in the first 3 months of life and disappears completely after 6 months. The absence of this reflex in the neonatal period indicates brain injury. The lack of startle reflex in one upper limb suggests paralysis of the brachial plexus due to birth injury or other causes or clavicle fracture. The startle reflex may be delayed or disappear when there is an injury or acute lesion in the brain. If it can still be elicited after 4 months, it should be noticed; if it still appears after 9 months, it is a characteristic of chronic lesions in the brain. Neurodevelopment is not just about the hug reflex, but also about the history of asphyxia and hypoxia, and the future neurodevelopment, as well as other physiological reflexes such as the feeding reflex, the sucking reflex, the holding reflex, the cross-extension reflex, the trunk and neck correction reflex, and the flexor muscle tone.