The U-shaped (or inverted U-shaped) relationship reveals the changing pattern of first decreasing and then increasing (or first increasing and then decreasing) between variables. It embodies profound management ideas such as "the extremes of things must be reversed" and "too much is not enough", and has important theoretical implications. and practical significance, but current management research has deficiencies in the construction and testing of U-shaped relationships. Based on the systematic exposition of the research progress of U-shaped relationships in management at home and abroad, this article proposes that the two different mechanisms of independent variables affecting dependent variables are the core of the construction of U-shaped relationships, and summarizes the three construction methods of the main effect of U-shaped relationships and The corresponding construction steps summarize the six steps of main effect testing and the three steps of moderating effect testing. This article integrates and summarizes the principles, procedures and methods of constructing and testing U-shaped relationships, which will help improve the quality of management research.