An impeller assembly is revealed. The impeller assembly includes a base arranged with at least one impeller. The base has a flow guide surface disposed with at least one mount location set thereof. The mount location set is composed of a plurality of locking slots and a mounting region while each locking slot connects the mounting region with the flow guide surface. The impeller includes a mounting part mounted into the mounting region of the base and a plurality of blades is arranged around the mounting part. A reinforcing piece is disposed between the inner edge of the blade and the mounting part for connection, and is mounted into the locking slot correspondingly. By such design, the structural strength of the weak region between the mounting part and the blade is increased and this favors precise location and assembly of the impeller with the base.