Objective To study the optimal insulin therapy in diabetic peritoneal dialysis patients. Methods In a cross-sectional study, 25 type 2 diabetic patients treated with peritoneal dialysis for at least 6 months were investigated. We reviewed their dialysis prescription, insulin therapy regimen and blood glucose control. We also retrospectively studied the changes of insulin doses and glycemic control in 24 new diabetic peritoneal dialysis patients. Results In the cross-sectional study, 23 of the 25 patients used insulin, 6 cases by intraperitoneally（IP）, 9 cases by subcutaneously（SC）, and 7 cases via the combined subcutaneous and intraperitoneal routes（IP+SC）. There were no significant differences in the fasting blood glucose, glycosylated hemoglobin, dialysate glucose concentrations, dialysate glucose load, dialysate doses among the three groups, whereas the insulin doses was significantly reduced in SC group as compared with the IP and IP+SC group (P<0.05). The peritonitis rate was higher in diabetics patients (1/15 per patient month) as compared to nondiabetic patients (1/48 per patient month) (P<0.01). After starting peritoneal dialysis in the 24 new patients, the insulin dosage was increased(0.33±0.23) times as compared to pre-dialysis insulin dose. There were no differences between practical and theoretical increase in insulin doses (P>0.05). Conclusion Our data suggest that subcutaneous insulin administration in peritoneal dialysis patients is more economic and convenience and is effective in blood glucose control. 