Enzymatic hydrolysis lignin was prepared and used to converse into aromatic aldehydes by catalytic wet oxidation with activation of Fenton reagent. The results demonstrated that the enzymatic hydrolysis lignin was a suitable raw material for the preparation of aromatic aldehydes. Orthogonal experiments were conducted to obtain the optimum preparation conditions. The effects of activation time, activation temperature, ratio of liquid to solid and pH of the reaction system on the yield of aromatic aldehydes were dealt with in this paper and optimal activation conditions were obtained as followed: the pH of activating reaction system was 4, activation temperature was 60°C, ratio of liquid to solid was 20:1 and activation time was 30 min. The highest yield of 13.74 % was obtained under the optimum conditions.