In 1986,the Archaeological Institute of Shaanxi Province evacuated a water saturated,rotten lacquer “Yu” from Qingong tomb No.1,at the Yongcheng site of Fengxiang city.No suitable method could be applied to dehydrate and reinforce the piece.The natural sand pile drying method can only be applied to lacquerwares that have a lower water content (around 50%,not higher than 100%) and well preserved wooden parts.A technical improvement has been made to this method.An acetone solution of gum mastic was added to the sand for dehydration and reinforcement of the water-saturated,rotten “Yu” lacquerware piece.As a result,the shrinkage of the longest length of “Yu” was zero,the shrinkage of its greatest width was 1.3%,and the absolute water content was 180%.There was no distortion and the colored drawing on the surface was saturated and colorful.The result is satisfying.The dehydration mechanism is:the gum mastic acetone solution reinforces the piece;the dehydration speed is controlled by the bulk of the sand and the surrounding sand decreased the distortion force.This modification overcame “the natural sand pile” drying method’s limitation to laquerware with low water content and well preserved wooden parts.The method can be applied on water saturated,rotten lacquerware and has broad applicability.