Product lifecycle management (PLM) is a concept that aims at integrating the various processes and phases involved during a typical product lifecycle for the extended enterprise. In order to maintain the integrity of product definition data throughout the life of the product, and to manage business processes used to create, manage, disseminate, share and use the information, this paper firstly explores the connotations of PLM; then presents a conceptual modeling framework including four-tier architecture; further models product lifecycle in the phases of requirement analysis, conceptual design, engineering design, manufacturing and services; and finally proposes an integration framework to support interoperability of distributed product data sources.