It has been a quite disputed question as to the function of the native language in the foreign language teaching and also a difficult choice for the foreign language teachers to make in their real classroom communication. But it seems that much attention has been paid to the negative influence of the native language. The study emphasis has been on the negative transfer of the native language, while little attention is paid to its positive effects. And this article tries to discuss the positive effect of the native language in the foreign language teaching on the basis of the theories of foreign language teaching and also explain how to practice in the foreign language classrooms. In a word, in the foreign language learning, as the learners' first language, their native language should act as a crutch, or an aid.