Epimedin C is one of the chemical markers and major flavonoids in Herba Epimedii (Yinyanghuo), which is traditionally used to treat bone diseases and gonadal dysfunction in China. Our previous study indicated that epimedin C could induce endothelial-like, but not osteogenic differentiation of C3H/10T1/2 cells in vitro. As vasculogenesis plays a pivotal role in bone formation, this study used the bone morphogenetic protein 2 (BMP2) induced ectopic bone formation model and mice 4T1 breast cancer cells co-implanted with luciferase labeled C3H/10T1/2 cells (4T1 [Formula: see text] C3H/10T1/2-Luc) model to examine the in vivo effects of Epimedin C on vasculogenesis. As a result, Epimedin C significantly increased the bone weight and blood perfusion of mice in the BMP2 induced ectopic osteogenesis model, and the bone in Epimedin C [Formula: see text] BMP2 group was more mature than that in BMP2 group. In addition, the tumor weight, blood perfusion and tumor-associated angiogenesis were also significantly increased in the Epimedin C treated 4T1 tumor bearing mice. The mRNA levels of endothelial markers, such as the platelet endothelial adhesive factor-1(CD31), the endothelial cell specific molecule-1(ESM-1), and the vascular von Willebrand factor (vWF) in mouse 4T1 mammary tumor tissue, were commonly found to occur alongside the luciferase (labeled in C3H/10T1/2 cells) expression and significantly increased after Epimedin C treatment. Taken together, Epimedin C can effectively promote vascularization both in the BMP2-depended bone formation model and in the 4T1 mammary tumor-bearing model by inducing an endothelial-like differentiation of C3H/10T1/2 in BALB/c nude mice.