Objective: To analyze the distribution of pathogenic bacteria in postoperative infectious endophthalmitis (IE) in cataract patients and to investigate the clinical significance of the cluster of differentiation 64 (CD64) index, soluble triggering receptor expressed on myeloid cells 1 (sTREM1) and high mobility group protein 1 (HMGB1) expression. Methods: 125 patients (125 eyes) with IE after cataract surgery who were treated in the Ophthalmology department of Jinan People's Hospital from January 2018 to July 2022 were selected as the IE group, and 150 patients (150 eyes) without IE after cataract surgery during the same period were selected as the non-IE group. The distribution of pathogenic bacteria in patients with postoperative IE was analyzed, CD64 index was calculated, and serum sTREM1 and HMGB1 expression were detected. Multivariate Logistic regression was used to analyze the influencing factors of postoperative IE in cataract patients. Receiver operating characteristic (ROC) curve was used to analyze the diagnostic value of CD64 index, serum sTREM1 and HMGB1 expression in the postoperative IE in cataract patients. Results: 138 strains of pathogenic bacteria were detected in aqueous humor or glass stock solution of 125 patients with postoperative IE, and Gram-positive bacteria, Gram-negative bacteria and fungi accounted for 81.88% (113/138), 16.67% (23/138) and 1.45% (2/138), respectively. Compared with non-IE group, the proportion of diabetes mellitus, vitreous overflow and CD64 index, serum sTREM1 and HMGB1 levels were elevated, and operation time is longer in the IE group (P<0.05). Multivariate Logistic regression analysis showed that diabetes mellitus, vitreous overflow, prolonged operation time and elevated CD64 index, sTREM1 and HMGB1 were independent risk factors for postoperative IE in cataract patients (P<0.05). ROC curve analysis showed that CD64 index combined with serum sTREM1 and HMGB1 predicted the area under the curve of postoperative IE in cataract patients significantly higher than that predicted alone. Conclusion: The pathogenic bacteria of postoperative IE in cataract patients are mainly Gram-positive bacteria, and CD64 index, serum sTREM1 and HMGB1 expression are independently correlated with postoperative IE in cataract patients, which may become auxiliary diagnostic indicators of postoperative IE.