A method for grouping wireless devices and an apparatus thereof are provided. First, the feature values of a plurality of access points (APs) detected by a wireless device are received, wherein these APs are designated as a first set, and the feature values of the APs constitute a feature vector. A first grouping process is performed to the wireless device according to the first set, which allocates the wireless device to an appointed clustering factory. A second grouping process is performed to the wireless device according to the feature vector, which divides all of the wireless devices within the appointed clustering factory into a member group or a noise group. Eventually, the grouping result is transmitted to the wireless device.