Abstract: Objective To investigate the relationship between atrial fibrillation (AF) and serum soluble CD163. Methods A total of 336 patients with heart valve disease were included in this study, including 167 with AF and 169 with sinus rhythm. The clinical data were compared between the two grops, and Logistic regression analysis was used to identify the risk factors associated with AF. Results The levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), tumor necrosis factor (TNF), interleukin-6 (IL - 6), high-sensitivity C-reactive protein (hs-CRP) and left atrial diameter (LAD) all differed significantly between the two groups (P<0.05). Serum soluble CD163 levels in AF patients were significantly higher than those in patients with sinus rhythm (P<0.05). Serum soluble CD163 was positively correlated with TNF (r=0.244, P=0.244), IL-6 (r=0.186, P=0.186), hs-CRP (r=0.183, P=0.183) and LAD (r=0.194, P=0.194) in patients with AF. Logistic regression analysis showed that LAD, IL-6, TNF, hs-CRP and CD163 were all associated with AF. ROC curve analysis showed that the area under curve of serum soluble CD163 was 0.861 in patients with AF (CI 95%: 0.820-0.901, P<0.01) with a sensitivity and a specificity of 80.8 and 76.9%, respectively. Conclusion Serum soluble CD163 level may be a risk factor for AF, and an increased soluble CD163 level may indicate active inflammation in AF patients.