Unexpectedly, L-proline/piperidine was found to be a better recyclable catalyst system than L-proline or piperidine alone in the condensation of acetone to prepare mesityl oxide (MO), an important intermediate in the chemical industry. Binding the catalyst system onto polymer resin enhanced the MO selectivity and reduced the catalyst loss. The mechanism of the bi-component catalyst system was also studied through control reactions, as well as by dynamic calculations. The MO selectivity could reach 74.4% and its isolated yield could reach 73.9%, based on the consumed acetone. Although the result does not immediately meet the requirement of industrial production, this study provides a novel organocatalyst system, which might offer a potential alternative to traditional inorganic catalysts that can be used under mild and neutral conditions.