Krashen has developed the Input Hypothesis, which has deep influence on teaching method of second language. This thesis focuses on the Krashen's Input Hypothesis, which includes the following five hypotheses: the acquisition- learning hypothesis, the monitor hypothesis, the natural order hypothesis, the input hypothesis and the effective filter hypothesis. The thesis tries to explore the pedagogical implications of Krashen's Input Hypothesis on second language teaching in the aspects of the input quantity and input quality. The thesis tries to explore the most effective methods of second language teaching, in the hope that it will help to improve the efficiency of second language teaching.
