1, with different scope of application. Abstract is a brief summary, written at the beginning of an academic paper or thesis, explaining the purpose of the paper and its main conclusions. The introduction can appear at the beginning of any article to attract readers to read further and let readers know the rest.

2. The purpose is different. According to the abstract, we can judge whether the rest of the content is of reference value and worth paying for reading. The introduction is mainly to stimulate readers' interest in reading.

3. Different format requirements. It can be divided into structured and unstructured. Structured abstracts are divided into background, purpose, methods, results and conclusions, which can help readers find relevant information quickly. Unstructured abstracts are usually used in non-scientific fields, and all parts are summarized in one paragraph. There is no format requirement for the introduction, which can be anecdote or fact.

4. The content written is different. There is no need for references, and the length is generally not more than 200-250 words. It is a minimalist version including methods, results and conclusions, and should be written from the background or purpose, so as to be concise but informative.

The introduction does not include methods, results or conclusions, but it still needs some more in-depth information, such as the explanation of assumptions and problems, the novelty and importance of the research, etc. The introduction should include references, and it is best to write it after all the papers are completed.