The invention relates to an aldol condensation catalyst composition, a preparation method thereof and a method for preparing methyl methacrylate by using the aldol condensation catalyst composition. The aldol condensation catalyst composition comprises an active component, an auxiliary agent, a polymerization inhibitor and a carrier, the carrier is SiO2, the active component is silicate of Cs, the auxiliary agent is oxide of Ce, and the polymerization inhibitor is selected from one or more of oxides of Bi, Zr, La, Cu, Mn and Fe, preferably copper oxide. According to the aldol condensation catalyst composition disclosed by the invention, polymerization of double-bond substances in a reaction system is inhibited, and the coking and carbonization rate of the surface of the catalyst is obviously reduced, so that the coking and carbon deposition resistance of the catalyst is improved, and the one-way service life of the catalyst is prolonged.