Exergy analysis has been performed on a single-shaft gas turbine with steam injection upstream (STIG) of the combustion chamber. The analysis will be performed to study the effect of increasing of compressor inlet temperature O1T design compressor pressure ratio cd PR and turbine inlet temperature O3T on the exergy destruction of STIG cycle components. For a specific value of steam mass flow rate: the increasing in O1T has a worthless effect on the exergy destruction of compressor and turbine while leads to increase in the exergy destruction of the combustion chamber. The increasing in cd PR leads to increase in the exergy destruction for all gas turbine power plant components. The increasing in O3 T leads to decrease in the exergy destruction of the combustion chamber, increase in the exergy destruction of the turbine, while has a worthless effect on the compressor. The biggest exergy destruction occurs in the combustion chamber For a specific values of O1T , cd PR , and O3 T steam injection will lead to improve the exergy destruction of the the combustion chamber, while has a reverse effect on the turbine, and has no effect on the compressor.