The static creep mechanism and behaviour of Al-Zn-Mg alloy have been investigated under condition of constant stress tension creep test in the temperature and stress range of 170-260℃, and 5-12.5㎏/㎟ respectively. The experimental result are follows ; The stress exponent value for creep was observed to about 7.3-6.43 and the activation energy for creep deformation was 44-41㎉/㏖. Larson-Miller parameter P for the crept specimens under the creep condition was obtained as P=(T+460) (log t_r+8.6). Emperical equation for the creep rate was obtained by the computer simulation as follows. 등식 Fracture was dominated by intergranular mechanism over the experimental range.