BackgroundType 2 diabetes mellitus is one of the most prevalent diseases， which imposes a heavy burden on patients' families and the society. Sleep disorders are recognized as risk factors for the development of diabetes， which may affect the onset and development of diabetes through neuro-endocrino-metabolic pathways， so identifying the factors responsible for the sleep quality of diabetic patients is of great importance in improving their sleep quality. ObjectiveTo investigate the relationship among fear of disease progression， executive function and sleep quality in patients with type 2 diabetes mellitus， so as to provide references for improvement of sleep quality in patients with type 2 diabetes mellitus. MethodsA sample of 197 patients with type 2 diabetes mellitus who were admitted to the Endocrinology Department of the Second Affiliated Hospital of the Air Force Military Medical University from January to May 2023 and met the criteria defined in the Guideline for the Prevention and Treatment of Type 2 Diabetes Mellitus in China （2020 edition） were consecutively selected. All subjects were assessed using Fear of Progression Questionnaire-Short Form （FoP-Q-SF）， Behavior Rating Inventory of Executive Function-Adult version （BRIEF-A） and Pittsburgh Sleep Quality Index （PSQI）. Then the Process macro for SPSS （Model 4） and Bootstrap technique were applied to examine the mediating effect of executive function on the relationship between fear of disease progression and sleep quality in patients with type 2 diabetes mellitus. Results①75 patients （38.07%） with type 2 diabetes mellitus were found to have sleep problems. ②PSQI score in patients with type 2 diabetes mellitus was positively correlated with FoP-Q-SF score and BRIEF-A score （r=0.159， 0.287， P<0.01）. ③Executive function mediated the relationship between fear of disease progression and sleep quality， the indirect value was 0.076 （95% CI： 0.022~0.146）， accounting for 39.58% of the total effect. ConclusionSleep disorders are common in patients with type 2 diabetes mellitus， and executive function may play a medicating role in the relationship between fear of disease progression and sleep quality.