In this study, a series of aryloxy-aluminoxanes originated directly from the hydrolysis of reaction products of AlMe_3 and phenols were synthesized, which could serve as effective polymer-retarding activators for the iron-catalyzed ethylene oligomerization.The molar ratios of [PhOH]/[AlMe_3] and [H_2O]/[Al] during the preparation were explored and their impacts on the oligomerization activity and product distribution were discussed. To obtain the effective activators with good polymer-retarding effect and relatively high activity, the optimized conditions were proposed to be [PhOH]/[AlMe_3] = 0.5 and [H_2O]/[Al] = 0.7. Various aluminoxanes with different[―OH] sources confirmed the importance of using phenols in preparing the effective polymer-retarding activators. By utilizing these aryloxy-aluminoxanes, the mass fraction of polymers in the total products could be reduced to lower than 1.0 wt%, which is much lower than that of the MAO-activated systems(> 30 wt%). This is a potential benefit for the industrial application of the iron-catalyzed oligomerization process.