For the purpose of offering foundations for quality of information system conceptual models, the quality characteristic of models was deduced based on ISO/IEC. This paper begins with the basic concept of information system, analyzes and nails down the relationship among information system quality, conceptual model quality and standard of software quality, points out six categories of quality characteristics of conceptual model such as maintainability based on ISO/IEC standard on software quality, one kind of which, operability, is defined. The consequence of this research may serve as a reference for standardization of conceptual model quality.