Based on the preload theory of the combined frame body of the press,the preload coefficient of the hot die forging press is determined by analyzing the preload process,and the concept of the preload cor-rection coefficient is proposed,and the difference between the two is analyzed.Finally,the preload process of the 2500t hot die forging press is analyzed by using the finite element analysis software,and the rationality of the selection of the preload coefficient is proved.It provides reference for dealing with similar problems in the future.