OBJECTIVE To evaluate the corneal structure change after phacoemulsification by anterior segment optical coherence tomography (AS-OCT). METHODS Phacoemulsification with 3.0 mm clear corneal tunnel incision were performed in 61 cataract patients (90 eyes). Corneal structure were scanned with the AS-OCT preoperatively, 2 d, 1 week, 1 month, and 3 months postoperatively respectively, and the parameters were analyzed statistically. RESULTS Gaping at the endothelial side of the wound in 56 eyes (62.2%), gaping at the epithelial side in 10 eyes (11.1%), and Descemet's membrane detachment in 27 eyes (30.0%) were observed 2 d postoperatively. 15.6% more of the eyes had gap at the endothelial side at 1 week postoperative, and 5.6% more at 1 month postoperative. Descemet's membrane detachment happened after incision lip in all of the eyes. The thickest site of incisional cornea was located before incision lip in all of the eyes. The incisional corneal thicknesses at variable postoperative time points were thicker than that of preoperative (P < 0.05). The incision thickness at 3 months postoperative was still significantly different from that of preoperative (P < 0.05). CONCLUSIONS The corneal structure changes after phacoemulsification. AS-OCT could provide sensitive and detailed observation and quantitative measurements of the changes.