Forkhead transcription factor O1 (FOXO1) methylation is associated with inflammation. Diabetic kidney disease (DKD) is characterized with increased inflammatory markers such as uric acid, hemogram indices, C-reactive protein derived markers, omentin and neuregulin. This study aimed to investigate the effect of DNA methylation in FOXO1 gene promoter, blood glucose and lipids in the process of type 2 DKD. Bisulfite genomic sequencing was used to monitor DNA methylation in the promoter region (+1021, +1193) of FOXO1 gene. The detections were taken in glycosylated hemoglobin A1c, fasting plasma glucose and blood lipid. 81 participants were divided into the control group, the preliminary diabetes mellitus group, the pure diabetes mellitus group, and the DKD group. The other groups displayed higher fasting plasma glucose than the control group (all P value < .05). The fasting plasma glucose level was higher in the pure diabetes mellitus group than the preliminary diabetes mellitus group (P = .004). The levels of HbA1c were higher in other groups than control group and preliminary diabetes mellitus groups (all P values < .01). The high-density lipoprotein level was lower in the DKD group (P = .021, P = .022) than control and pure diabetes mellitus group. The levels of low-density lipoprotein were statistically lower in preliminary diabetes mellitus and DKD groups than control group (all P value < .02). Along with the progress of DKD, a down trend was observed in the total methylation rate of FOXO1 gene (P = .025), which contains 5 CpG sites (1021, +1193) in the promoter. Hypomethylation in the promoter of FOXO1 gene, hyperglycemia and low level of serum lipid might be associated with the pathogenesis of type 2 DKD.