With the acceleration of globalization, China tends to communicate more with western countries, especially with those developed countries whose native language is English, in order to establish stronger commercial, political and cultural bonds with them. As a result, foreign language learning, especially English learning has been emphasized to a large extent in recent years, when the study of linguistics has been paid much attention for its function of guiding English teachers and learners to teach and learn English efficiently and scientifically. This paper intends to analyze why linguistic study is necessary for language learners.