Abstract: Objective To evaluate the predictive value of the systemic immune inflammatory index (SII)-prognostic nutritional index (PNI) score for the prognosis of patients with colon cancer after radical surgery.Methods A retrospective analysis was conducted using clinical data from 144 patients with colon cancer who underwent radical surgery in the Affiliated Hospital of Xuzhou Medical University from January 2015 to December 2016. The optimal cutoff values for SII and PNI were determined using the receiver operating characteristic (ROC) curve. The patients were grouped based on the cutoff values and assigned SII-PIN score. The relationships between different groupings and the clinicopathological characteristics and prognosis of patients with colon cancer after radical surgery were analyzed.Results The area under the ROC curves of SII and PNI was 0.695 and 0.754, respectively, with the optimal cutoff values of 658 and 48.95. According to the cutoff values, the SII-PNI score was divided as follows:SII<658 and PNI>48.95 were 0 point (61 cases); SII ≥ 658 or PNI ≤ 48.95 was 1 point (41 cases); SII ≥ 658 and PNI ≤ 48.95 were 2 points (42 cases). COX multivariate regression analysis showed that the degree of tumor differentiation, infiltration, TNM stage, and SII-PNI score were the independent risk factors affecting DFS in colon cancer patients (P<0.05), while the degree of tumor differentiation, TNM stage, and SII-PNI score (2 points) were the independent risk factors affecting OS in colon cancer patients (P<0.05). The survival curve showed that the survival rate of group 0 point with SII-PNI score was significantly higher than those of group 1 point and group 2 points (P<0.05).Conclusions The preoperative SII-PNI score is an independent risk factor affecting patients with colon cancer, and can be used to evaluate the prognosis of patients after radical resection of colon cancer.