One-step syntheses of methyl isobutyl ketone are studied over palladium supported on aluminophosphate molecular sieves: SAPO-11 and AlPO4-11. The effects of reaction condition, metal loading, acidic and basic properties, pore size and methods of metal loading are investigated. The results show that a balance between the condensation and hydrogenation is necessary for high selectivity of MIBK. Basic sites promote the activity. The selectivities of MIBK are improved by loading Pd by ion-exchange, occlusion in the pores or acid treatment of the support. Close contacts of the mutifunctional sites are necessary for higher selectivity