Novel catalysts of phosphotungstic heteropolyacids (PW1,2) supported on neutral alumina were prepared by assistance of ultrasound and plasma treatment. The prepared catalysts were characterized by FT-IR pyridine adsorption (Py-IR), temperature programmed desorption of Pyridine (Py-TPD), BET and X-ray diffraction (XRD), and their catalytic performances were evaluated by the cationic polymerization of tetrahydrofuran. The results indicate that plasma treatment remarkably increases the surface acidity of the prepared catalyst while ultrasonic treatment induces PW1,2 to uniformly disperse on the support surface and expose more active sites for the acid catalytic reaction. A higher catalytic activity (69.7%) is obtained on the novel catalyst, which significantly outstripped that on the conventional sample (57.5%).