Firstly, the paper describes the concept of knowledge representation and a variety of knowledge representation. Secondly, it discusses tree levels of knowledge representation: implementational level, logical level and epistemological level. For each level, it sets a framework for comparing and evaluating intelligent knowledge representation. Then commonly-used knowledge representation schemes are compared with this framework. It is believed that this framewok can be efficiently used for comparsion and selection of nowledge representation scheme in spromblem solving.