A robot cleaner system is disclosed. The robot cleaner system includes a robot cleaner to carry out a cleaning operation while automatically traveling around along a surface to be cleaned, and a charging station connectable with the robot cleaner to charge a charging battery mounted in the robot cleaner with electricity. The charging station includes a setting switch to selectively set up a value of threshold height. The robot cleaner includes a control unit to receive the value of threshold height set up at the charging station from the charging station, to store the received value of threshold height in a memory, to compare a value of threshold height detected by a height sensor of the robot cleaner in traveling of the robot cleaner with the value of threshold height stored in the memory, to control the robot cleaner to travel while crossing over a threshold when the detected value of threshold height is the same as and less than the stored value of threshold height and to control the robot cleaner to travel after backing up and rotating when the detected value of threshold height exceeds the stored value of threshold height.