With the emergence of models such as chatGPT and Baidu AI Wenxin Yiyan, the research and application of NLP (Natural Language Processing) is increasingly centered on PLM (Pretrained Language Model),It marks that the current machine learning model has reached a new height. This article first introduces the background of the large language model, and introduces pre-training + fine-tuning and the current popular Prompt from the four major paradigms of NLP. Understand the workflow and function of Prompt, focusing on Prompt engineering, and structures, and looking ahead to future challenges for Prompt.