【Abstract】A large number of critics have studied primary school English language teaching from the perspective of critical period hypothesis. In this thesis， the author will first provide readers with primary opinions of critical period hypothesis and then an overview of the researches on studying English language teaching in primary schools from the perspective of critical period hypothesis over the past few years.
　　【Key words】Critical Period Hypothesis; Literature Review; Primary School; English Language Teaching
　　1. Primary Opinions of Critical Period Hypothesis
　　There is a long-standing debate on the existence of Critical Period. Supporters and offenders are equal in terms of number， but they have reached an agreement on the following three opinions. Firstly， “The Optimum Age” does exist. Second language acquisition also has the optimum age and that age is between two years old to ten years old. （Gao， 10） Secondly， the formation of pure voice does have a critical period. Stromswold points out accurate linguistic competence tests show that there is little possibility for children who get in touch with a target language after teenager to approach his pronunciation to the native speakers’. He（2001 cited from Gui.X.2011） Thirdly， the ultimate achievement of second language acquisition does have a critical period. Stern and Ellis claim that adult learners are faster in second language acquisition than children learners. But in the long run， children learner will eventually achieve higher achievement than adult learner. （Gao， 14）
　　2. Literature Review on Studying English Language Teaching in Primary School
　　The author of this thesis reviewed a large number of theses on Enlish language teaching in primary schools from the perspective of critical period hypothesis and makes the following conclusions. Most of the research findings obtained are quite similar to the findings obtained by those critics who focus on studying English language teaching in preschool education. Age is not the determining factor and we should also take other factors such as students’ intelligence difference， the faculty and so on into consideration. Based on the above finding， most critics doubt the scientificalness of the policy that students start learning English from the third grade in primary school. They think primary schools should first guarantee the English teachers’ quality， the faculty factors and the language acquisition environment and then stimulate students’ subjective initiatives. Otherwise， primary schools should delay English teaching to a higher grade. 　　Based on critical period hypotheses， Cao Ning （2008， 99） comes up with some other constructive suggestions. She proposes that first language acquisition has a closer relationship with foreign language acquisition. In foreign language acquisition， any positive transfer utilization and negative transfer restraint are based on the profound comprehension of mother tongue. The function of mother tongue is implacable for foreign language learners in the native language environment. Also， along with the further study， foreign language will in turn enhance the first language acquisition. So， foreign language and mother tongue should interact with each other. Mei Yuan （2001， 139） states that the plasticity of brain during teenager is in high vitality and language imitation ability is also very active. Teenagers have exquisite and powerful sense of hearing and less mental disorders. So， adolescence is the optimum period to learn oral English. She also proposes that primary schools should be equipped with foreign teachers in order to let students contact with authentic pronunciation and oral English. Also， teachers should let them understand learning English is mainly for communication.
　　3. Conclusion
　　Based on the above proposition made by the above critics，the author of this thesis makes some conclusions as follows. Firstly， primary schools should delay English teaching to a higher grade if they can not guarantee the faculty factors， the language acquisition factors and teachers should spare no effort to stimulate students’ own subjective initiatives. Secondly， primary schools should put Chinese and English education at the equal status rather than over exaggerating the function of English education. Thirdly， primary schools should pay more attention to improver students’ oral English.
　　References：
　　[1]Cao.N.2008.On Critical Period Hypothesis and “English Learning Begins in the Early Childhood”.Journal of Wuhan Institute of Technology.pp.99-103.
　　[2]Gao.J.2007.On Baby English Education.Shanghai：East China Normal University Press.pp.14-16.
　　[3]Gui.X.2011.Preschool English Education from the Perspective of Critical Period Hypothesis，Journal of Educational Development，pp.36-38.
　　[4]Mei.Y.2002.On Critical Period Hypothesis and Primary，Middle school and Colleges，pp.137-139.