Abstract: OBJECTIVE To explore the etiological characteristics of the patients with pelvic inflammatory disease and analyze the diagnostic values of serum high-mobility group protein B1 (HMGB1), interleukin-2 (IL-2) and monocyte chemotactic protein 1 (MCP-1). METHODS A total of 102 patients with pelvic inflammatory disease who were treated in Huanggang Central Hospital from Mar 2020 to Dec 2022 were assigned as the case group and were divided into the mild group with 28 cases, the moderate group with 44 cases and the severe group with 30 cases according to the severity of pelvic inflammation. 110 healthy people who received physical examination were chosen as the control group. The Chlamydia trachomatis, Mycoplasma urealytium and Gonococci as well as the levels of serum HMGB1, IL-2 and MCP-1 were compared among the groups, the result of drug susceptibility testing for the M.urealytium was statistically analyzed, and the values of serum HMGB1, IL-2 and MCP-1 in diagnosis of pelvic inflammatory diseases were analyzed. RESULTS The incidence rates of C.trachomatis, M.urealytium and Gonococci infections of the case group were higher than those of the control group, the incidence rates of the infections of the severe group were higher than those of the moderate group and the mild group, and the incidence rates of the infections of the moderate group were higher than those of the control group (P<0.05). The levels of serum HMGB1 and MCP-1 of the case group were higher than those of the control group, the levels of the indexes of the severe group were higher than those of the moderate group and the mild group, and the levels of the above indexes of the moderate group were higher than those of the control group (P<0.05). The serum IL-2 level of the case group was lower than that of the control group, the serum IL-2 level of the severe group was lower than that of the moderate group and the mild group, and the serum IL-2 level of the moderate group was lower than that of the control group (P<0.05). The 102 patients with pelvic inflammatory diseases were highly resistant to ciprofloxacin and levofloxacin. The areas under curves (AUCs) of serum HMGB1, IL-2 and MCP-1 were respectively 0.897, 0.937 and 0.928 in diagnosis of pelvic inflammatory diseases, and there was no significant difference among the three indexes. CONCLUSION The C.trachomatis, M.urealytium and Gonococci infections are associated with the occurrence and severity of the pelvic inflammatory disease. The M.urealytium is highly resistant to ciprofloxacin and levofloxacin. The patients with pelvic inflammatory disease show high expressions of serum HMGB1 and MCP-1 and low expression of serum IL-2. The three indexes are associated with the severity of pelvic inflammation, and the three indexes have high values in diagnosis of the pelvic inflammatory disease.