Cinnamaldehyde (one kind of unsaturated aldehydes) was hydrogenated to hydrocinnamaldehyde (one kind of saturated aldehydes), cinnamyl alcohol (one kind of unsaturated alcohols) and hydrocinnamyl alcohol (one kind of saturated alcohols). Gas (hydrogen)-liquid (organic solution, reactant and products)-liquid (alkaline aqueous solution)-solid (catalyst) four phases existed in a batch reactor. The selectivity was significantly varied by two kinds of catalysts. Reaction kinetics were studied by using Pd/C or Pt/C as a catalyst. When Pd/C was used, hydrocinnamaldehyde was the main product and the formation rate was 0.012 mol/(s kg-cat). When Pt/C was used, cinnamyl alcohol was the main product and the formation rate was 0.0013 mol/(s kg-cat).