This article begins by accounting the development of Second language theories. It describes major ESL theories ever since the 18th century to those currently adopted in ESL field. Then it proceeds to demonstrate their influences on EFL teaching in China, like nowadays an increasing awareness of non-cognitive factors in teaching foreign languages, reforms in some traditional teaching methodologies to satisfy the current demand for temporary EFL learners and ever-increasing case studies in new teaching modes. Lastly the author points out some problems existed in current EFL teaching and learning in the hope of drawing the attention of teachers and researches in this field.