Previous studies showed that the samples of saturated soft clay undergoing several stages of impact loading and reconsolidation show obvious quasi-overconsolidation state,and have an increased shear strength. In this paper,the definition of quasi-overconsolidation ratio is given,and furthermore a model for predicting the shear strength of saturated soft clay after impact loading is suggested. In this model,the conditions of partial drainage and stages of impact are taken into account. The calculation results by the proposed model are in good accordance with test data. Besides,the effect of disturbance consolidation on the undrained shear strength by this model is discussed.