Abstract: Provided is a combined cycle (CC) unit standby system with integrated auxiliary gas turbine generator (Aux. GT), including: a plurality of first gas turbines, a plurality of heat recovery boilers, a steam turbine, a condenser, at least a second gas turbine generator and a control unit. As such, the present invention incorporates at least a second gas turbine generator of small capacity into the CC unit standby system, the pipelines and components of each unit are kept in a hot state, to facilitate the rapid load increase during restart process, to save energy during the standby period, accelerate the restart process and reduce the energy consumption during the starting phase, and also keep the unit in “House Load Operation” state, stay independent from the power grid to cope with the emergency situation of black start, improve the restart and energy efficiency in standby and shutdown states.