Palladium-catalyzed Suzuki coupling reactions are regarded as one of the most effective methods for making C-C bonds; however, a green synthesis to substitute the use of abundant organic solvents has been a challenging problem. Herein, two commercial hydrophilic MgOs with different sizes were selected to support the highly dispersed Pd nanoparticles (NPs) due to the strong host-guest interactions and good hydrophilicity. When (Pd/MgO)(nano) was applied to catalyze the Suzuki-Miyaura reaction in aqueous solution, the (Pd/MgO)(nano) exhibited much better catalytic performance than (Pd/MgO)(bulk). Particularly, (Pd/MgO)(nano) also exhibited significantly higher catalytic performance than the commercial Pd/C catalyst (95 vs 62%) due to its excellent hydrophilicity. Besides, the solvent effects, temperature effects, substrate tolerance, and so forth have been systematically investigated to further demonstrate its catalytic performance. More importantly, (Pd/MgO)(nano) s till retained about 87% of catalytic activity after six successive cycles, indicating its great potential in industrial applications.