Ammonium and silver co-doped phosphotungstic acid was developed as novel efficient catalyst for the synthesis of n-butyl levulinate. The catalyst was characterized by element analysis, FT-IR, XRD and Hammett indicator method. Among them, (NH4)(0.5)Ag0.5H2P12O40 exhibited the highest catalytic activity, and the yield of n-butyl levulinate could reach up to 99.0% within 2 h. The results showed that the activity of (NH4)(0.5)Ag0.5H2P12O40 was higher than that of single Ag+ or NH4+ doped H3PW and other representative catalysts reported by literatures. In addition, (NH4)(0.5)Ag0.5H2PW12O40 performed good reusability for this reaction. (C) 2016 Elsevier B.V. All rights reserved.