The invention discloses a wind generation set impeller assembling device which is characterized by comprising an installation seat (1) used for positioning and supporting a hub (5), and multiple impeller installing devices used for installing an impeller (6) and the hub (5) in an aligned mode. The impeller installing devices are respectively connected with the installation seat (1) so as to form an impeller assembling platform. The installation seat (1) is provided with a plurality of connection portions (10) which are connected with the impeller installing devices respectively. When the impeller is assembled, the hub (5) is arranged on the installation seat (1), each variable pitch bearing of the hub (5) corresponds to one impeller installing device, the impeller (6) is placed on one corresponding impeller installing device and moved to one corresponding variable pitch bearing of the hub (5), so that the impeller and the hub are connected. According to the wind generation set impeller assembling device, the impeller and the hub can be fast aligned and positioned, installing the impeller is fast, the structural design is simple, and the wind generation set impeller assembling device is convenient to use and applicable.