During general anesthesia, patients require effective and reliable monitoring methods for pain assessment, but there is still a lack of unified monitoring tools. In recent years, there have been a variety of pain monitoring tools using different techniques, which however have not been unanimously recognized. Based on related researches at home and abroad, this paper briefly reviews the research progress on perioperative pain monitoring through discussing the principles, clinical application, effectiveness, reliability, advantages and disadvantages of different monitoring tools, so as to provide reference for pain monitoring studies.