Objective To explore the effect of apoptosis and venous remodeling in the varicosity. MethodsBy using TUNEL, Van Gieson collagen staining, venous wall image and transmission electron microscope, 83 patients with varicosity and 10 controls were studied. ResultsApoptosis and apoptosis index of ECs and SMC in cystic dilatations were compared with those of non-cystic dilatations and controls with significant difference(P＜0.01). The collagen content in patients with cystic dilatations and non-cystic dilatations were higher than that of controls (P＜0.05, P＜0.01). The venous wall of cystic dilatations become more thinner(P＜0.01). The regression and correlation analysis showed that collagen contents and SMC apoptosis index had significant effect on venous wall (r=0.9777,P＜0.001 and r=-0.5432, P=0.003) respectively. Electron microscopy confirmed apoptosis of ECs and SMC in varicosity. Conclusion Increased collagen content, increased cell apoptosis and reduced cell component lead to venous remodeling, and it may be one of the mechanism of varicosity.