Abstract: It is of great significance to evaluate the effect of forced compression treatment for spring and to predict the storage life and load loss of springs. In this paper, the stress relaxation test of cylindrical spiral compression spring was carried out. Started from the stress relaxation modified equation based on dislocation movement, the accelerated test data were fitted and analyzed, and a method to evaluate the effect of forced compression treatment for spring was proposed. Then, the new stress relaxation equation was linearized, and the spring life prediction equation and load prediction equation were derived respectively, and the method for calculating the load loss error was given, and the life and load loss of the cylindrical spiral compression spring were predicted, and it was verified by experiment. The results show that the spring stress relaxation equation is effective and the error of load loss prediction is within ±2%.