In semantics-based component retrieval ontology is usually employed as the semantic basis for component representation and matching. Existing methods always assume that the ontology already exists. However, ontology construction itself is a big challenge and the construction of ontology for component retrieval has its own characteristics differing from general domain ontology, including the emphasis on functional semantics, the explicit instance set (i.e. semantic descriptions of all the components stored in the repository) and the explicit objective of characterizing components for retrieval. In this paper, we propose an incremental and FCA (Formal Concept Analysis) based ontology construction method. The feature of incremental ontology construction means a collaborative and interactive process with component providers to collect basic input/output descriptions of components. FCA with the extension of hierarchical-valued concept context is adopted to elicit concepts from original component descriptions to construct ontological hierarchy for functional concepts. After concept analysis, semantic representation of each component can also be filled automatically. So our method can alleviate the efforts of ontology construction remarkably and the quality can also be ensured in terms of the requirements of component retrieval.