AIM: To investigate the correlation between 25-hydroxyvitamin D and metabolically associated fatty liver disease in type 2 diabetes mellitus. METHODS: A total of 2 406 subjects in Standardized Metabolic Disease Control were recruited from the National Center for Standardized Metabolic Disease Control in The First Hospital of Lanzhou University. The population was divided into Q1, Q2, Q3 and Q4 according to 25(OH)D quartile. The prevalence of MAFLD and related clinical indicators among the four groups were compared, and the influencing factors of MAFLD were analyzed by Logistic regression. Restricted cubic spline (RCS) was used to explore the relationship between 25(OH)D and MAFLD. RESULTS: The prevalence of MAFLD was different with different vitamin D levels. The prevalence of MAFLD was lower in the group with high 25(OH)D level. The level of 25(OH)D in patients with MAFLD was lower than that in patients with T2DM alone, and the number of vitamin D deficiency was relatively higher. Multivariate regression analysis showed that 25(OH)D was not associated with the risk of MAFLD. RCS analysis also suggested that 25(OH)D was not associated with the risk of MAFLD. CONCLUSION: The prevalence of MAFLD is high in people with low vitamin D level, and vitamin D is not associated with the risk of MAFLD after multivariate adjustment.