Language transfer is a very important phenomenon in second language acquisition(SLA), which many linguists and psychologists would like to research. People who learn second language must be familiar with the rules of their mother tongue, so they often transfer those rules into the second language unconsciously, and then transfers appear. Language transfer divided into positive and negative transfer. The article use Odlin’ s definition of language transfer in SLA. Language transfer is a very important phenomenon in second language acquisition (SLA), which many linguists and psychologists would like to research. People who learn second language must be familiar with the rules of their mother tongue, so they often transfer those rules into the second language unconsciously, and then transfers appear. Language transfer divided into positive and negative transfer. The article use Odlin ’s definition of language transfer in SLA.