Abstract: Chen Yun attached great importance to the construction of Sanmenxia Reservoir, and his attitude in the process of policy making of the project was very careful and dispassioned.Before the start of some important and significant projects, adequate arguments and extensive discussions must be carried out;in the process of construction of projects, we should find out the potential problems in time and should take some efficient and useful measures to solve the problems;and we should assume the responsibility and draw a lesson from the mistakes once we find out that we have made some mistakes in policy making.Above are the great experiences which Chen Yun left to us in the process of construction of Sanmenxia Reservoir.