Background Perioperative hyperglycemia was associated with postoperative infection, and proper management of perioperative glucose has become critical in improving the prognosis of patients. Methods A total of 1015 diabetic patients who underwent surgery and received insulin treatment for their hyperglycemia in our hospital were retrospectively reviewed. According to propensity matching, we obtained 253 pairs of patients from the group which received continuous subcutaneous insulin infusion (CSII) therapy (CSII group) and the group which received insulin injection therapy (non-CSII group). Perioperative glucose levels and corresponding outcomes were compared between the two groups. Results Compared with the non-CSII group, the CSII group had lower fasting and mean glucose levels, lower incidence of fever (operation day: 18.6% vs 10.2%; P = .014; first postoperative day: 55.1% vs 34.7%; P < .001), a positive rate of postoperative secretion culture (6.3% vs 1.2%; P = .004), and a shorter time of antibiotics use (total antibiotics use: P = .002; postoperative antibiotics use: P < .001) and hospital stays (P < .001). However, there was no difference in the total medical expenditure between the two groups (P = .499). Further analysis showed that CSII therapy was superior to multiple daily insulin injection (MDI) therapy in its effect on infection and other postoperative outcomes when 64 pairs of patients from the CSII group and MDI group were compared. Conclusions CSII therapy provides better perioperative glucose control and a lower risk of postoperative infection without increasing the total medical expenditure. Highlights In our study, we adopted propensity matching, which included 1015 patients and 30 types of surgeries. The results show that patients who receive continuous subcutaneous insulin infusion (CSII) therapy have a lower incidence of perioperative fever, a lower positive rate of postoperative secretion culture, and a shorter duration of antibiotic use. These results indicate that CSII therapy reduces the risk of postoperative infection and improves the prognosis of patients.