The upper and lower eyelids in humans are medically referred to as the upper and lower eyelids. If some of the fibers of the levator muscle extend upward and attach to the skin of the upper eyelid 3-5mm from the lid margin, when the levator muscle contracts, the eyelid is lifted upward and the surface of the upper eyelid forms an inner narrow and outer wide distinct crease, a horizontal furrow, which is the principle of double eyelid formation. The main types of double eyelids include parallel, open, fan, crescent and European eyes. The crescent type is wide in the middle and narrow on both sides, the fan type is narrow on the inside and wide on the outside, the parallel type is about the same width on the inside, middle and outside, and the European type is wider, like the big wide double eyelids of Europeans. However, oriental people are more suitable for parallel type, crescent type, fan type and open fan type, and it is not recommended to do European style eyes. Double eyelid surgery requires choosing the right style according to the anatomical shape of each person’s eyelids, eyebrow-eye distance, face shape and temperament, not too wide or too narrow, too wide gives a more aggressive, fake and uncoordinated look, while double eyelids that are too narrow can cause weakening or disappearance of the heavy eyelid line as the upper lid skin relaxes over time. Therefore, it is recommended that candidates visit a regular hospital, consult an experienced doctor, combine their own characteristics and choose a double eyelid that suits their facial features, and not blindly pursue European-style eyes.