Vascular stem cells (VSCs) play an important role in vascular remodeling such as neointima formation. However, the relative contribution of VSCs and smooth muscle cells (SMCs) to the proliferative SMCs remains controversial. Here we use lineage tracing models to compare the expansion and differentiation potential of VSCs (Sox10+) and SMCs (MHC+). Single cell analysis showed that VSCs proliferate at a much higher rate than SMCs, and the derived cells demonstrated the phenotype of myofibroblasts and proliferative SMCs, suggesting that VSCs are a major contributor of traditionally defined proliferative SMC population. In addition, VSCs have the potential to differentiate into osteoblastic and adipogenic cells. In vivo lineage tracing showed that neointima might contain either a major population of VSC-derived cells or a large population of SMCs, suggesting different mechanisms of neointima formation. Furthermore, we demonstrated that VSCs contribute to the formation of microvessels during tissue regeneration. These results highlight the important roles of VSCs in vascular remodeling, and may lead to the development of new therapy strategies to treat vascular diseases and to promote tissue regeneration.