The effect of solvent on the epoxidation of propylene with H2O2 over TS-1 has been investigated, and the spent catalysts were characterized by TG analysis and FT-IR spectra. The results show that both the activity and the selectivity of TS-1 decrease with the length of carbon chain of the alcohol solvent; TS-1 exhibits high selectivity with low activity in aprotic solvent; using H2O as the solvent, both the activity and the selectivity of TS-1 are quite low. The differences in the depositing amount and the depositing species in the spent catalysts show that, the nature of the solvent plays an important role in the propylene epoxidation. The formed by-products mainly depend on the nature of solvent besides the Bronsted acid site of the catalyst. (C) 2004 Elsevier B.V. All rights reserved.