Upper blepharoplasty is the most popular procedures in China and East and Southeast Asia. A variety of technical methods are used because the mechanism of the formation of double eyelid in the Asians is still controversial. Sayoc's theory that double eyelid is formed by the fusion of fibers from the levator aponeurosis and the pretarsal skin gains a majority support, but has never been proved in Asian eyelid. We carried on an anatomic study about the inferior part of the upper eyelid using both electron microscope and light microscope, and found direct evidence of the existence of this connection, which confirmed Sayoc's theory. This anatomic structure and motor system is then confirmed in clinical attempting of reapproximating them in upper blepharoplasty in thousands of Chinese patients by perfect satisfied results in terms of zero postoperative blepharoptosis rate, naturally looked appearance, and significantly shortened recovery time.