Abstract: Supported Cs₂O solid base catalysts were prepared with Cs₂CO₃ as catalyst precursors and γ-Al₂O₃, MgO, CaO, TiO₂, SiO₂ and NaY molecular sieve as supports at calcination temperature of 700℃. These catalysts were used to catalyze transesterification reaction for biodiesel production from rapeseed oil. The results showed that solid super bases could be prepared with γ-Al₂O₃, MgO and CaO, and γ-Al₂O₃ was the optimal support considering both transesterification ratio and separation performance. The optimal process conditions preparing solid base with Cs₂CO₃ and γ-Al₂O₃ were as follows: calcination temperature of 700℃, calcination time of 5 h and atmosphere of N2. Transesterification ratio reached 95.5% when using the catalyst prepared under these optimized conditions.