Concentrated H₃PW₁₂O₄₀ (HPW) was first employed to decompose cellulose under microwave irradiation at low temperatures. 75.6% yield of glucose was obtained at 90 °C under microwave irradiation for 3 h, which was considerably high under such mild conditions using phosphotungstic acid as a catalyst. With the same effective acid concentration, HPW gave the highest cellulose conversion and glucose yield among the Brønsted acid catalysts, indicating that the strong Brønsted acid played an important role during cellulose hydrolysis. In the hydrolysis of cellulose with HPW as catalysts, microwave irradiation led to higher glucose yields than the conventional heating method. The recovery and reusability of HPW were investigated by extraction with diethyl ether from the reaction solution. At the same time, the performance of the concentrated HPW for real lignocellulosic biomass (corncob, corn stover and bagasse) hydrolysis was also investigated.