The project of Virtual Observatory (VO) is the result of breakthroughs in telescope, detector, computer and Internet technologies. The combination with the new information technology is the major characteristic of the VO development. Extensible markup language (XML) and Grid as two trends of information technology will be adopted widely in the VO. XML and the related technologies are used for information storage and exchanging within the VO. The VO architecture is based upon the standard layered architecture of Grid. In the paper, technologies related in each layer of the VO architecture are introduced. The global virtual observatory provides new chances for Chinese astronomy. Using the abundant resources in the Internet and chances provided by open-source software, Chinese astronomers should cooperate with national IT experts and push the virtual observatory projects of China as soon as possible.