In this paper, a module-based hierarchical microgrid (MG) structure is proposed to help rural electrification. It provides a bottom-up way to form a MG with multilayer expandability. The proposed MG overcomes the drawback of conventional MG that requires high upfront cost and long leading time. It provides an organic way to form a MG that allows user to scale up the system while demands growing, which can fully utilize the existing resources. The proposed MG is expandable on different layers that can meet requirements from customers with all power consumption levels.