The aim of this study was to evaluate the effect of using a mobile medical application (app) for self-monitoring of blood glucose (SMBG) and blood glucose control in young patients with newly diagnosed type 2 diabetes mellitus (T2DM). This was a prospective cohort study involving young patients with newly diagnosed T2DM. On a voluntary basis, the patients chose to be included in a group in which they were followed up for 24 weeks with a mobile medical app and the changes in laboratory data and frequency of SMBG observed via the app, or in a group in which they received traditional medical treatment and follow-up. The results between the two groups were compared. A total of 126 patients signed the informed consent form and were enrolled in the study, of whom 66 chose the mobile medical group, which used the mobile medical app, and the remaining 60 patients chose the traditional medical treatment model. The differences in the physical and chemical indicators between the app-using group and the traditional medical model group were not statistically significant at baseline (p > 0.05). At 24 weeks of treatment, the levels of glycosylated hemoglobin A1c (HbA1c), total cholesterol, triglycerides, and low-density lipoprotein cholesterol were significantly reduced in all patients compared to before treatment (p < 0.05). The app-using group had a higher HbA1c compliance rate and higher frequency of both SMBG and doctor-patient communication than the traditional medical model group (p < 0.01). The HbA1c compliance rate of patients using the mobile medical app was 1.53-fold higher than that of the traditional medical model group. At 24 weeks, HbA1c was negatively correlated with the frequency of SMBG (r = - 0.208, p = 0.020) and the frequency of doctor-patient communication (r = - 0.323, p = 0.000). Additionally, there was a positive correlation between the frequency of SMBG and doctor-patient communication (r = 0.579, p = 0.000). A mobile medical app is helpful to young patients with newly diagnosed T2DM for monitoring their blood glucose level and improving their blood glucose control to meet the standard.