An assembly tool for assembly and replacement of bolts on a wheel hub is revealed. The tool includes a first tool set and a second tool set. The first tool set has a base and a fastener. The base is a circular body with a receiving part. A pad is disposed on the receiving part and a bearing is arranged under the pad. The fastener includes a hexagonal head, an enlarged part, a cylindrical part and an axial hole arranged with a thread. The second tool set has a first arm and a second arm pivotally connected to each other. A wheel bolt is pressed into the wheel hub by the first tool set while the wheel hub is positioned by the first and second arms of the second tool set fastened with the wheel bolts of the wheel hub for convenient assembly of the wheel bolts.