This study concentrates upon synchronous online teaching using multimedia and different softwares. This paper analyses the relationship between online teaching by the means of digital library techniques and effectiveness &efficiency of learners using digital libraries as virtual means. Three models, which can explain online teaching on digital library techniques, are established and tested. UsingLISREL8.80 program, it explained 57% of reading activities, 46% of listening activities, and 35% of watching activities of the learners (using digital library techniques), with good models fit. The subjects make use of the multimedia in fulltime and multi-tasks such as searching, browsing, downloading (audio and video), copying text, listening and watching audio & video, reading, writing, extracting and abstracting information. They also use chat room for more discussions in the category of online collaborative and finally report their information in different styles through assignments, projects on WWW, or face-to-face in the classroom..