For hydrogenation of dibenzo 18 crown 6 the catlalyst RuO 2 on alumina was used instead of reported Pichler ruthenium. The separation and purification processes of the targ et product also have been improved. The method is much simple, economic and time saving. For hydrogenation of dibenzo 18 crown 6 the catlalyst RuO 2 on alumina was used instead of reported Pichler ruthenium. The separation and purification processes of the targ et product also have been improved. The method is much simple, economic and time saving.