PROKB(PROlog Knowledge Base) is one of four memories in Sphinx system, which is an integrated developement tool for constructing a knowledge-based system. PROKB is used to deal with knowledge with some dynamic features to a specific application domain, while the other three memories are used for rule-based systems. Knowledge representation in PROKB is based on multiple schemes which support semantic networks, frames, and object-oriented programming on the basis of logic programming paradigm. Therefore, various advantages can be obtained from the uniform formalism. They include information clustering, taxonomic structuring, procedural reasoning in addition to formal reasoning and property inheritance, and proof-theoretical semantics. In this thesis, both declarative and procedural knowledge representation schemes are presented as an associated framework for constructing PROKB. Knowledge definition, question answering facilities with corresponding Knowledge Definition Language(KDL), and query language are also presented. Finally, Concept Editor is presented as an interactive user-interface for knowledge representation.