Today , the main data source of data mining is historical databases which mainly include text and numerical data . the data mining on multimedia data on www , specially , image and video , lacks enough research . this paper discussed some basal problems about multimedia , including definition , theories and technologies that multimedia data mining needs , system structure and model 本文首先简单阐述了数据挖掘和知识发现的基本理论；然后分析了网络信息检索与挖掘的特征，特别是web数据挖掘和基于内容的多媒体检索；进而探讨了www上基于内容的多媒体数据挖掘的一系列基本问题，包括定义、挖掘对象的特征与分类、挖掘和发现所需的理论和技术以及系统的框架结构和功能模块的分析与设计等，力图为该方向的深入研究提供一些有益的思路。
