AIM:To discuss the characteristics of corneal topography for keratoconus patients and provide objective and feasible basis for diagnosis of keratoconus. And to conduct strict screening on corneal refractive surgery patients using corneal topography to increase the predictability of the operation. METHODS:Eleven cases of keratoconus patients and 11 eyes of suspected keratoconus patients used the SIRIUS 3D corneal topography instrument to check. The morphology of corneal anterior and posterior surface topography, central corneal refractive power, inferior and superior central corneal difference of average refractive power (I-S) and surface asymmetric index (SAI)were obtained. RESULTS: Keratoconus corneal thinnest point was not in the central cornea,but located to the top of the cone of the third quadrant, and surrounded by the concentric circles with refractive power gradually reduced.The difference in central corneal refractive power between keratoconus and suspected keratoconus had statistical significance. Keratoconus and suspected keratoconus corneal thickness difference was statistically significant difference.The highest points on corneal anterior and posterior surface and corneal thinnest point of keratoconus and suspected keratoconus were generally identical in SIRIUS 3D corneal topography, which accorded with the trend of the development of keratoconus. Its vectogram has a certain significance in the judgement of keratoconus. CONCLUSION: The SIRIUS 3D corneal topography is an effective method of early diagnosis of keratoconus, providing a reliable basis for the patients screening before corneal refractive surgery.