AIM:To explore the influence factors of the treatment zone diameter(TZD)and its correlation with axial length growth(ALG)after Paragon CRT orthokeratology.METHODS: Retrospective clinical study. The data of 226 myopic patients(226 eyes)wearing Paragon CRT orthokeratology from April 2020 to September 2022 were collect. The correlated factors of TZD after wearing lens for 1mo, and the relationship between the overlapping treatment zone/ pupil area ratio and the ALG after wearing lens for 1a were analyzed.RESULTS: After wearing lens for 1mo, the TZD was negatively correlated with central corneal thickness(CCT)and positively correlated with the flat corneal eccentricity. After wearing lens for 1a, the ALG of the small TZD group(0.25±0.18mm)was significantly smaller than that of the large TZD group(0.34±0.24mm, P=0.002), and the ALG of the small area ratio group(0.24±0.19mm)was significantly smaller than that of the large area ratio group(0.35±0.23mm,P<0.001). Age and overlapping treatment zone area/pupil area ratio were significantly associated with the ALG in multivariate linear regression(all P<0.05).CONCLUSION: The wearers with thicker CCT and smaller flat corneal eccentricity usually had smaller TZD, and both the TZD and the overlapping treatment zone area/pupil area ratio were correlated with the ALG.