AIM: To investigate dynamic changes of posterior corneal power and astigmatism after cataract surgery based on Pentacam three-dimensional anterior eye segment analyzer.METHODS: Totally 96 elderly patients(116 eyes)with cataract underwent phacoemulsification combined with intraocular lens implantation in our hospital from January 2019 to January 2020 were selected. Parameters including anterior corneal power, posterior corneal power, flat keratometry, steep keratometry, mean keratometry, anterior corneal astigmatism, posterior corneal astigmatism, and total corneal astigmatism were obtained using Pentacam three-dimensional anterior eye segment analyzer system at postoperative 1wk, 1mo and 3mo. Spearan correlation analysis was performed on the anterior segment. RESULTS: The anterior corneal power(flat keratometry, steep keratometry, mean keratometry)was lower at postoperative 1wk than that before operation, and began to return to the preoperative level at postoperative 1mo and 3mo. The posterior corneal power and total corneal power(flat keratometry, steep keratometry, mean keratometry)were higher at postoperative 1wk than before operation, and began to stabilize at postoperative 3mo. The anterior corneal astigmatism, posterior corneal astigmatism, and total corneal astigmatism were also higher at postoperative 1wk than before operation, and began to decrease and stabilize at postoperative 3mo. The anterior corneal power was significantly positively correlated with total corneal power; The posterior corneal power was significantly negatively correlated with the total corneal power, and was significantly positively correlated with its absolute value(P<0.05). The total corneal astigmatism before operation and at postoperative 1wk and 3mo was significantly positively correlated with anterior corneal astigmatism at corresponding time points(P<0.01), while showed no significant correlation with posterior corneal astigmatism.CONCLUSION: Changes of posterior corneal power and astigmatism can be observed with 3mo of cataract surgery, and Pentacam three-dimensional anterior eye segment analyzer system can accurately assess the dynamic changes of anterior and posterior corneal power and astigmatism before and after operation, which is of great clinical value.