As port-based description (PBD) can conveniently capture the definition of component,it is easy to synthesize product design schemes.Ports are generally defined as the location of intended interaction between components and their environments.They constitute the interface of a component,and define its boundary in a system configuration.The process of port creation is clearly related to component,and it is the basis of the product concept generation.This paper introduces an approach to a port-based functional modeling framework for product conceptual design.A port-based knowledge building process is described for functional modeling.This research proposes a method of creating and managing different ports.First,this paper presents the function and impact of ports,gives port definition and port representation between components.Second,describes port attributes and three port types that they are mechanical port,electrical port and configuration port,and gives port attributes of compatibility.Then,presents port based modeling design process,that is,three main modules:the language of port description,port-based FBS representation and port knowledge management.Three knowledge layers are specialized for function,behavior and structural knowledge.They represent different abstraction levels of the product conceptualization.Each layer is represented with description logic for a uniform representation.We provide formal definitions of the framework to manage port knowledge.Finally,the process of port-based functional modeling is presented in a thermal bubble jet application to demonstrate the effectiveness of the research.