Hot compression tests of the Al-9.39Zn-1.92Mg-1.98Cu alloy are carried out in the temperature range from 300 ?C to 460 ?C and the strain rate range from 0.001 s-1 to 1 s-1, and the height reduction degree is 70%. The flow stress is corrected because of the effect of friction. Results show the flow stress decreases with increasing the temperature increasing or decreasing the strain rate. The friction effect is more and more obvious when the temperature is low and the strain rate is high. A revised constitutive equation considering the influence of strain is established based on the Arrhenius-type model. Compared with the experimental and predicted flow stresses, the revised constitutive equation has a higher accuracy. Their correlation coefficient and average absolute relative error is 0.95 and 2.45%, respectively.