Based on CBSE (component-based software engineering), this research on composable embedded software investigates the theory, methods and technologies for modeling and verification of embedded components. The paper surveyes the state-of-the-art research and practices on composable embedded system from three perspectives: composite theory, modeling, and verification techniques. It introduces the optimistic and pessimistic definitions of component compatibility, and composition mechanisms including operations and rules. In modeling techniques, the paper particularly addresses the issues of composition of non-functional attributes and heterougeneous components, which are important to embedded components design and verification. It analyzes non-functional attribute constraints and multi-attributes oriented model. The paper also investigates three typical verification techniques of component composition including contract-based, invariants-based, and model checking techniques. It discusses future works in the end.