Objective ·To observe the changes of vascular morphology and blood flow in the macular area of the fundus of type 1 diabetic children without retinopathy by optical coherence tomography angiography (OCTA), and explore the application of OCTA in these children. Methods ·From June 2019 to February 2020, 27 type 1 diabetic children without retinopathy (54 eyes, observation group) who were hospitalized in the Department of Endocrinology of Shanghai Children′s Hospital, Shanghai Jiao Tong University School of Medicine, and 25 age-matched healthy children (50 eyes, control group) were selected. The macular area of the fundus of the two groups of children was scanned with OCTA in the range of 3 mm×3 mm and 6 mm×6 mm, respectively, and the morphology of the macular arch ring was observed. The area of foveal avascular zone (FAZ), and the vascular density and perfusion density of different zones around the foveal were quantitatively analyzed Results ·The morphology of the macular arch ring in the observation group was regular, and the FAZ area of macular area was larger than that in the control group (P=0.000). The superficial retinal vascular density and perfusion density within the diameter of 1 mm around the macular fovea were lower than those in the control group (P=0.009, P=0.012). In the observation group, the superficial retinal vascular density and perfusion density in the area outside 1 mm diameter and within 3 mm diameter around the macular fovea were (18.29±0.96) mm^-1 and 0.43±0.03, while the superficial retinal vascular density and perfusion density in the area outside 3 mm diameter and within 6 mm diameter around the macular fovea were (18.58±0.69) mm^-1 and 0.46±0.02, which had no significant difference with the control group. Conclusion ·In the children with type 1 diabetes mellitus, the enlargement of macular arch and the decrease of superficial retinal vascular density and perfusion density within 1 mm diameter around macular fovea may occur before retinopathy. OCTA can be effectively applied to the early monitoring of the changes of vascular morphology and blood flow in the macular area of the fundus of diabetic children.