1. The preface should not be too long, generally between 200 and 300 words, and the postgraduate thesis is not limited.

2. The preface should be concise, and all contents need to hit the nail on the head. There is no need to repeat the existing knowledge or obvious functions or meanings in general textbooks in the preface.

3. Don't explain the basis of the topic by yourself, but quote the previous literature to explain why the author chose this topic, its necessity and urgency.

When talking about your own research work in the preface, you should seek truth from facts and avoid making arbitrary assertions. Don't use the words "initiative", "first discovery", "no previous research", "reaching the domestic advanced level", "approaching the world level" and "filling the domestic gap".

5. When telling the value and significance of the paper, we should proceed from the problems mentioned in the paper, take the preliminary work and actual needs as the premise, leave room objectively, but make it clear. Because only the author can understand the value and significance of the paper best, so we must make it clear for readers to understand and judge.

6. We should objectively introduce the research work done by predecessors in related fields, and never deliberately belittle it to avoid adverse consequences.

7. The preface should be closely related to the theme of the paper, and rhetoric should be used less to prevent digression. Don't use cliches such as "little knowledge" and "limited level" in the preface.

8. Don't write the preface as a summary or a note to the summary, and at the same time avoid duplication with the text.