Objective:To explore the risk factors of postoperative depression in patients with esophageal cancer, and to develop a risk prediction model which providing a theoretical basis for the early detection of depression in high-risk groups by clinical staff.Methods:From September 2022 to March 2023, at the South Campus of Affiliated Hospital of Jiangnan University, 269 hospitalized patients with esophageal cancer (191 in depression group, 78 in non-depression group) were selected as the model construction set. From March to May 2023, at the South Campus of Affiliated Hospital of Jiangnan University, 78 hospitalized patients with esophageal cancer were selected as the external validation set. The patients with Beck depression inventory-Ⅱ score ≥5 and depression diagnosed by two experts (chief psychiatrists of the Department of Psychiatry of Affiliated Hospital of Jiangnan University) were considered as depression and included in the depression group, and the other patients were enrolled in the non-depression group. The general data, blood routine examination, high-sensitivity C-reactive protein (hs-CRP), blood electrolytes, blood lipids, clinical symptoms (gastroesophageal reflux, sleep disturbance, appetite, etc.) and depression score were compared between the depression group and the non-depression group. Independent sample t-test and Mann-Whitney U test were used for statistical analysis. Multiple logistic regression model was performed to analyze the independent risk factors of postoperative depression in patients with esophageal cancer, and a risk warning model was constructed. The Hosmer-Lemeshow test and receiver operating characteristic curve (ROC) were used to evaluate the fitting degree and predictive efficiency of the model, and the cross-validation method was used to verify the effectiveness of the model. Results:The incidence of postoperative depression in patients with esophageal cancer was 71.0% (191/269). The total white blood cell count, hs-CRP, blood phosphorus β 2 microglobulin and the proportion of sleep disorders of the depression group were higher than those of the non-depression group (1.3 (1.1, 5.4) ×10 9/L vs. 0.9 (0.3, 1.1) ×10 9/L, 75.8 (54.8, 102.1) mg/L vs. 60.8 (3.6, 61.5) mg/L, (1.33±0.32) mmol/L vs. (1.02±0.19) mmol/L, (2.17±0.72) mg/L vs.(2.12±0.49) mg/L, 84.3% (161/191) vs. 33.3% (26/78), and the differences were statistically significant ( Z=9.24, 7.88, t=9.24, χ2=67.87 t=1.98; all P<0.001); hemoglobin, total platelet count, high-density lipoprotein (HDL) and the proportion of poor appetite were lower than those of the non-depression group ((119.91±24.51) g/L vs. (122.09±22.97) g/L, (203.43±58.45)×10 9/L vs. (311.55±83.54)×10 9/L, (1.04±0.30) mmol/L vs. (1.43±0.23) mmol/L, 73.3% (140/191) vs. 84.6% (66/78)), and the differences were statistically significant ( t=-2.00, -8.42 and -8.48, χ2=3.96; P=0.047, <0.001, <0.001, =0.047). The results of multifactorial logistic regression model analysis showed that sleep disorder ( OR=3.976, 95% confidence interval (95% CI 1.601 to 9.872)), loss of appetite ( OR=0.271, 95% CI 0.092 to 0.791), white blood cell count ( OR=31.808, 95% CI 2.879 to 351.401), hs-CRP ( OR=1.031, 95% CI 1.017 to 1.044), platelet count ( OR=0.990, 95% CI 0.982 to 0.997), and HDL ( OR=0.017, 95% CI 0.001 to 0.242) were independent influencing factors of postoperative depression in patients with esophageal cancer. The formula of risk warning model was probability of depression=1-1/{1+ exp[1.544+ 1.380×sleep disturbance (yes=1, no=0)-1.307×loss of appetite (yes=1, no=0)-0.010×platelet count (×10 9/L)-4.063×HDL (mmol/L)+ 0.030×hs-CRP (mg/L)+ 3.460×white blood cell count (×10 9/L)]}. The results of Hosmer-Lemeshow test showed that the model has a good fit ( χ2=2.01, P=0.981), with an area under the ROC of 0.949, a sensitivity of 0.874, and a specificity of 0.872. The cross-validation of the external validation set showed that the accuracy of the risk warning model was 67.9%. Conclusion:This study is a preliminary study on the risk warning model of postoperative depression in patients with esophageal cancer, which provides a novel approach for screening depression in patients with esophageal cancer after surgery.