Air conditioning system with switches to block the standby power and its operating method

An air conditioner with standby power blocking switches and an operation method thereof are provided to block connection between an outdoor unit or indoor units and a main power supply if no control commands are received by any one of the indoor units, thereby realizing economical power management and promoting control convenience for an air conditioner manager. An air conditioner with standby power blocking switches includes an outdoor unit(10) connected to a first switch(SW1) to be turned on or off for supplying or blocking power from a main power source. A main indoor unit(21) has a control part(22) for on/off-control of a second switch(SW2), which is connected to the main power source, to supply or block standby power for more than one other indoor units(20) connected to the outdoor unit, and for off-control of the first switch connected via a communication line(L2) when no control commands are input from any one of the indoor units. The indoor units carry out air conditioning by the power supplied from the outdoor unit via communication lines(L) when the first switch is on. The indoor units standby inputs of operation commands by the standby power supplied from the main indoor unit via a communication line(L1) when the second switch is on.