Disclosed are a cleaning robot system and its method for controlling which make it possible to reliably and quickly clean with the aid of the cleaning robot. The cleaning robot system comprises at least one external device each formed of an indicator and a virtual wall setting function, with the aid of which cleaning work can be performed by the unit of blocks about a cleaning area reference point, not leaving non-cleaned area behind. Since the access of the cleaning robot can be restricted by means of a virtual wall set by an external device, any damages of furniture due to a collision of the cleaning robot can be prevented, and the cleaning robot can be barred from escaping from the set cleaning area.