Objective:To identify the factors influencing 24 h mean amplitude of glycemic excursion (MAGE) in patients newly diagnosed with type 2 diabetes. Methods:We analyzed the clinical data of 110 patients with type 2 diabetes without treatment. The 24 h MAGE was calculated using 3 d continuous glucose monitoring system (CGMS). Baseline data of patients were collected, and serum hemoglobin A1c(HbA1c), fasting blood glucose(FBG) and postprandial 2 h blood glucose(PBG), insulin and C peptide levels, blood lipid profiles, hepatic and renal functions were measured before treatment. Results:HbA1c was an independent index for 24 h MAGE in newly diagnosed type 2 diabetes mellitus patients (P < 0.05). MAGE in patients with HbA1c < 9.9% was lower than that with HbA1c ≥9.9%(5.97 mmol/L vs. 7.43 mmol/L, P < 0.05). HbA1c in patients with HbA1c < 8.5% was effected mainly by PBG, while FBG was an independent factor influencing HbA1c in newly diagnosed type 2 diabetes mellitus patients with HbA1c≥9.2%(P < 0.001). HbA1c in patients with FBG < 10.84 mmol/L was lower than that with FBG≥10.84 mmol/L (9.10% vs. 10.87%, P < 0.001). Conclusion:HbA1c is an independent factor of MAGE and closely related to FBG in patients newly diagnosed with type 2 diabetes mellitus.