A theoretical study of the performance of a CCHP system using natural gas as fuel which consists of gas turbine-steam turbine combined cycle, absorption refrigeration unit and exhaust heat boiler under variable loads was carried out. Two methods to adjust the electric and cooling loads are employed here. One method is to increase the outlet pressure of the steam turbine in the Rankine cycle. Another way is to change the air coefficient of the gas turbine. The calculation results show that the first method can obtain higher energy efficient and is the preferred method. The second way can be employed in case that further more cooling is required.