In this paper, the selective catalytic hydrogenation of p-tert-butyl-α-methyl cinnamaldehyde (PTBMC) to lilial over 5wt.%Pd/C was investigated. Results showed that K2CO3 modification of the catalyst remarkably improved the reaction rate and the selectivity of lilial. The effect of solvent, temperature, pressure and the initial concentration on the reaction was studied. The conversion of PTBMC is 100% and the selectivity of lilial was up to 98.5% under optimal reaction conditions: c (PTBMC) =0.375mol/L, 40 ℃, 0.5MPa.