Formononetin is one of the main active components of traditional Chinese medicine red clover (Trifolium pratense L). Prior studies have demonstrated that formononetin is a typical phytoestrogen and exhibits an estrogen-like effect that protects the cardiovascular system with minimal side effects. In this study, we further investigated the role of formononetin in human umbilical vein endothelial cells (HUVECs) and its potential molecular mechanisms. We founded that formononetin promotes proliferation and migration of HUVECs as assessed by the MTT and wound healing assays. Meanwhile, insulin-like growth factor 1 (IGF-1) and intercellular adhesion molecule 1 (ICAM-1) protein levels were increased in a dose-dependent manner. Our findings illustrated that formononetin exhibits a protective effect on HUVECs, and the molecular mechanisms may correlate with IGF-1R and ICAM-1, as well as upregulation of vascular endothelial growth factor (VEGF) and activation of extracellular signal-regulated kinase (ERK).