Objective To investigate the rate and the influencing factors of progression from impaired fasting glucose (IFG) to diabetes mellitus without drug intervention by continuous observation for 10 years in physical examination population. Methods A total of 557 people aged over 18 years who had physical examination in our hospital from 2008 to 2018 were included. The data of fasting blood glucose, blood pressure, total cholesterol and triglyceride were collected at every physical examination. The progression rate to diabetes mellitus in IFG patients diagnosed in 2008 and patients with normal fasting blood glucose progression to IFG were analyzed. Diabetes mellitus was defined as fasting blood glucose ≥ 7.0 mmol/L, or with a history of diabetes mellitus, or having been treated with insulin or oral hypoglycemic drugs; IFG was defined as no history of diabetes mellitus, receiving no hypoglycemic therapy, and fasting blood glucose being 5.6-6.9 mmol/L; normal fasting blood glucose was defined as no history of diabetes mellitus, receiving no hypoglycemic therapy, and fasting blood glucose <5.6 mmol/L. Binary logistic regression was used to analyze the influencing factors of progression from IFG to diabetes mellitus. Results There were 283 males and 274 females, aged 39 (19-69) years. Twenty-five cases (4.5%) were diagnosed with diabetes mellitus, 30 cases (5.4%) with IFG, and 502 cases with normal fasting blood glucose in 2008. In the 30 IFG cases, 14 (46.7%) cases progressed to diabetes mellitus within 10 years and 11 (36.7%) cases within 5 years. The proportion of patients with fatty liver (FL) and the level of triglyceride in the progressed group were higher than those in the non-progressed group within 5 years (both P<0.05). Among the 502 cases with normal fasting glucose in 2008, 177 cases progressed to IFG within 10 years, and 20 cases progressed to diabetes mellitus during the subsequent follow-up. The proportion of FL patients and triglyceride level in the progressed group were significantly higher than those in the nonprogressed group (both P<0.01). Binary logistic regression analysis showed that triglyceride was an independent risk factor for people with first diagnosis of IFG and then progressed to diabetes mellitus and those with normal initial fasting blood glucose and then progressed to IFG and further to diabetes mellitus (OR=2.43, 95% CI 1.03-5.70, P<0.05; OR=1.50, 95% CI 1.12-2.01, P<0.05). Conclusion IFG is an important stage of progression from normal fasting blood glucose to diabetes mellitus, and triglyceride is an independent risk factor for IFG to diabetes mellitus.