Component-based development (CBD) techniques have been widely used to enhance the productivity and reduce the cost for software systems development. However, applying CBD techniques to embedded software development faces additional challenges. For embedded systems, it is crucial to consider the QoS attributes, such as timeliness, memory requirement, output precision, power consumption, etc. When a system is composed of components, the appropriate components have to be selected such that the composed system is guaranteed to satisfy its QoS requirements. In this paper, we investigate the model for composition analysis. Based on the analysis model, we develop algorithms for selecting components to compose the designated system such that the overall system QoS properties can be Pareto optimal. An overview of a repository-based embedded software development methodology was first presented. Then we discuss the composition analysis techniques. A case study is presented to illustrate our approach finally.