Introduction, also known as preface, belongs to the introduction part of the whole paper. Its writing contents include: reasons, purposes, background, previous work and knowledge gap, theoretical basis and experimental basis, expected results and its position, role and significance in related fields.

The text of the introduction should not be lengthy, the content selection should not be too scattered and trivial, and the wording should be refined to attract readers to continue reading. There is no rigid and uniform regulation on the length of introduction, but it needs to be determined according to the size of the whole paper and the needs of the content of the paper. It can be as long as 700~800 words or 1000 words, or as short as 1000 words.