By using digital information, such as graphic image and audio as well as vedio, the integration of situational teaching of foreign language and modern multimedia technology enriches the content of foreign language teaching, which provides a rich and colorful environment for English learner. It can stimulate emotional students� experience and enhance their willings of participating in interacting with classmates by reasonably creating a situation around content of courses in teaching. Based on cognition of teaching method of situational teaching theory, this paper constructs functions to analyze the advantages of multimedia technology in situational teaching of foreign language, thus deduces applied purpose and principle of multimedia technology in situational teaching of foreign language by using the mathematical model to construct thoughts. It provides theory basis and new way of teaching practice for situational teaching of foreign language.