The performance of seven different gas turbine cycles are investigated versus the change of the gas turbine inlet temperature (TIT) which ranged from 773K to 1373K keeping ambient air temperature 294K, pressure ratio 9 and air flow rate 37 kg/s constant. The corresponding performances are expressed in terms of: fuel consumption rate, power output, thermal efficiency and specific power output for the seven cycles. From the results it is found that both of the turbine inlet temperature (TIT) and cycle arrangement have a great effect on the thermal performance of the gas turbine cycle. At the maximum turbine inlet temperature (TIT) 1373K, it is found that the highest obtainable power output is produced by the modified cycle4 while the highest obtainable efficiency is produced by the modified cycle6