Objective: To monitor the vascular function of children/adolescents with type 1 diabetes (T1D), assess the effects of long-term and short-term glucose fluctuation on vascular function, and explore the effects of different ways of insulin use and blood glucose monitoring on glycemic control and vascular function. Methods: Vascular function relevant data of 38 children with T1D were collected. According to well-controlling criterion as HbA1c <7%, they were divided into the well-controlled group (HbA1c <7%) and the poorly controlled group (HbA1c ≥7%). According to the different ways of insulin use and blood glucose monitoring, it was divided into the insulin pump or CGMs group and the traditional treatment group (4 times daily subcutaneous insulin injection and multiple fingertip blood glucose monitoring). Recording and calculating age, course of disease, high density lipoprotein (HDL) cholesterol, triglyceride (TG), low density lipoprotein (LDL), body mass index (BMI), systolic blood pressure (SBP), standard deviation of blood glucose (SDBG), largest amplitude of glycemic excursions (LAGE), postprandial glucose excursion (PPGE), glycosylated hemoglobin standard deviation (HbA1c-SD), urine albumin creatinine ratio (ACR), flow mediated dilation (FMD). Results: There were no significant difference in the indicators of vascular function, FMD and ACR in two groups (P>0.05), whether HbA1c was met to standard or not. FMD was negatively correlated with BMI, SDBG and LAGE; ACR was negatively correlated with age, course and BMI, while ACR was positively correlated with HbA1c-SD (P<0.05). Multiple regression analysis: FMD was mainly decided by the SDBG, BMI (P<0.05), and the proportion of SDBG was the largest. ACR was mainly affected by age and HbA1c-SD (P<0.05). In insulin pump or CGMs group, SDBG (2.6±0.8 vs 3.5±1.1), LAGE (6.4±3.6 vs 9.6±4.3), PPGE (2.2±1.0 vs 3.8±1.5), FMD (19.4±8.9 vs 12.5±10.4) had statistical differences from traditional treatment group (P<0.05). But, there were no significant differences in HbA1c-SD and ACR between two groups (P>0.05). Conclusion: It cannot predict the vascular function of children with T1D according to HbA1c level. In clinical practice, besides the level of HbA1c, more attention should be paid to the harm of blood glucose fluctuations to blood vessels. In children/adolescents, FMD can be used as the monitoring index of T1D large vascular function, while ACR can monitor microvascular function. Using CGMs or insulin pump can better manage blood glucose, reduce blood glucose fluctuation, be more meaning helpful for blood glucose control, so as to improve vascular function. However, no protective effect on microvascular function was found.