Error analysis, also known as error analysis, has a long history. Early error analysis mainly collected common errors and classified them from the perspective of language structure. Its main purpose is to provide a basis for facilitating the arrangement of teaching projects or the counseling of courses. It has no theoretical framework, nor does it explain what role errors play in second language acquisition. Therefore, people have neither given a strict definition of errors nor discussed the causes of errors from a psychological point of view. In 1950s, when comparative analysis became popular, bias analysis was even more neglected. At the end of 1960s, contrastive analysis began to decline, and people began to study interlanguage on the basis of first language acquisition. As a result, error analysis began to be valued again. Error analysis is helpful to understand the process of second language acquisition and to the study of interlanguage. In addition to providing information on the development of interlanguage, it is more important to provide information on the psychological process of interlanguage acquisition and provide useful clues to help students understand how to use various strategies to simplify their learning tasks and complete their communicative activities. Since the late 1960s, the British applied linguist Cod has published a series of articles on error analysis, and in the early 1980s, he published his monograph Error Analysis and Interlanguage. Cod believes that the specific operation of error analysis should include the following steps:

A) select language materials. The selection of language materials includes determining the size, form and consistency of language samples. The sampling objects should be basically the same in age level, mother tongue background and second language level.

B) Find out the mistakes in the sample. When identifying errors, we should distinguish between oral errors or clerical errors and errors, and also pay attention to the difference between obvious errors and invisible errors.

C) Describe and classify errors from the perspective of grammar.

D) Explore the causes of errors from the perspective of psycholinguistics.

E) Assess the seriousness and universality of mistakes, and provide basis for counseling.

The most important contribution of error analysis is that it improves the position of errors and changes our view of errors. People used to think that mistakes in second language learning were very harmful and should be avoided as much as possible. The study of interlanguage and error analysis makes people realize that errors are the concrete manifestation of students' progress in second language acquisition.