A robot cleaning system and a dust removing method of the same that are capable of moving a first dust collector mounted in a robot cleaner to a docking station to remove dust collected in the first dust collector. The robot cleaning system includes a robot cleaner having an opening, though which a first dust collector to collect suctioned dust is carried in and out of the robot cleaner, a docking station, to which the robot cleaner is docked to remove the dust collected in the first dust collector, and a collector moving unit to move the first dust collector to the docking station.