ObjectiveTo observe the changes of retinal and choroidal blood flow density and thickness in macula of different myopic dioptre eyes, and to analyze the correlation between retinal and choroidal blood flow density and axial length (AL). MethodsA retrospective clinical study. From October 2022 to May 2023, 86 eyes of 56 myopic patients scheduled for refractive surgery in Hubei Clinical Center of Laser Ophthalmopathy were included into the study. According to the equivalent spherical specular degree (SE), 19, 21, 27 and 19 eyes of low myopia group (group A), moderate myopia group (group B), high myopia group (group C) and super high myopia group (group D) were observed. Optical coherence tomography angiography (OCTA) and AL measurement were performed in all patients. The diopter was expressed in SE. AL was measured by ultrasonic bio-meter. OCTA scanner was used to scan the macular region in the range of 3 mm × 3 mm. The software automatically divided the macular region into two concentric circles with the fovea as the center, which were 1 mm in diameter respectively, the paracentric fovea of 1-3 mm was divided into 5 regions: superior, nasal, inferior and temporal. The superficial capillary plexus (SCP), deep capillary plexus (DCP), choroidal capillary plexus (CC), choroidal blood flow density, retinal and choroidal thickness were measured. The correlation between AL and blood flow density and thickness was analyzed by Pearson correlation analysis. ResultsThere was no significant difference in SCP blood density and DCP blood density in the fovea in groups A, B, C and D (P＞0.05) .There were significant differences in DCP flow density among superior, nasal, inferior and temporal areas (P＜0.05), the difference was significant (P＜0.05). There was no significant difference in the fovea area between the four groups (P＞0.05), but there was significant difference in the superior, nasal, inferior and temporal areas (P＜0.05). Different macular regions: there were statistically significant among group A, group B, and group C, group D (P＜0.05). Results of correlation analysis, AL was negatively correlated with DCP blood flow density (r=－0.504, －0.500, －0.460, －0.465), retinal thickness (r=－0.348, －0.338, －0.312, －0.230), macular Subarea CC (r=－0.633, －0.666, －0.667, －0.710, －6.82), choroidal layer (r=－0.635, －0.687, －0.659, －0.703, －0.680) and choroidal thickness (r=－0.665, －0.605, －0.656, －0.648, －0.643) (P＜0.05). ConclusionsAL is negatively correlated with DCP, CC, CDF, retinal and choroidal thickness in the eyes with myopia. SCP, DCP and retinal thickness in fovea did not change significantly, and temporal choroidal thickness changed earlier than other areas.