Aim To investigate the relationship between fibrinogen (FIB) and the progression of coronary plaque stenosis rate in patients with type 2 diabetes mellitus (T2DM). Methods Hospitalized T2DM patients who underwent two or more coronary CT angiography (CCTA) examinations in the First Affiliated Hospital of Xi'an Jiaotong University from January 2015 to December 2020 were included. The subjects were divided into high FIB and low FIB groups according to the median of FIB. The differences in the progression of coronary plaque stenosis rate and other clinical characteristics were compared between the two groups, and the relationship between FIB level and the progression of coronary plaque stenosis rate was analyzed by Spearman's correlation analysis and Logistic regression. Results A total of 145 patients were included, 73 in the high FIB group and 72 in the low FIB group at baseline, with a median follow-up time of 25 (8,0) months between CCTA. The age, proportion of women, and the progression of coronary plaque stenosis rate were higher in the high FIB group than those in the low FIB group, and the differences were statistically significant (P＜0.05). FIB level was positively correlated with the change in coronary plaque stenosis rate (r²＝0.308, P＜0.001). Multivariate Logistic regression analysis showed that FIB level was a risk factor for the progression of coronary plaque stenosis rate in patients with T2DM (OR＝5.5,5%CI:1.97～14.02, P＜0.001), after adjusting for age, sex and other clinical risk factors. Conclusion High baseline FIB level is an independent risk factor for the progression of coronary plaque stenosis rate in patients with T2DM, and monitoring FIB level is beneficial to cardiovascular risk stratification in patients with T2DM.