This paper describes the concept and the important sig nificance of the"Digital Earth". It is pointed out that the earth observing t echnology is the key issue of the"Digital Earth". It has been suggested that China should develop the national earth observing system. The system should cons ist of three parts, i.e., information acquisition, information processing and in formation application. The development of earth observation technology, in the f irst priority, have been discussed in the article. The national earth observing system could have a great contribution for the Digital Earth.