AIM:To investigate the clinical significance of corneal thickness measurement difference between optical coherence tomography(OCT)and corneal pachymeter.METHODS:The clinical data of corneal thickness in 102 cases 199 eyes measured by ultrasonic corneal hymeter and OCT were analyzed by statistical test.RESULTS:The thicknesses were 532.478±29.49μm and 541.47±29.00μm from OCT and ultrasonic corneal pachymeter respectively,there was statistical significance by paired t-test.It was divided into 4 groups by corneal thickness standardized on ultrasonic thickness measuring,paired t-test showed that when the corneal thickness≤500μm,500μm <corneal thickness≤550μm,550μm<corneal thickness≤600μm,there were all statistical significances between ultrasonic corneal pachymeter and OCT,when the corneal thickness>600μm,no comparison was done for little cases.CONCLUSION:Traditional ultrasonic corneal pachymeter and OCT showe some differences and better clinical conformance on measuring corneal thickness and can be used as reference before excimer laser surgery.