Abstract: Characteristics of compressive curves with different preconsolidation pressures p_c,withcon-sideratiOn of rectification of natural void ratio e_o,from Which the conceptions of little value and quasi--little value are analysed. A theoretical Method, in which quasi-little value is regarede as base point toappoach the true value of p_c,is proposed. Results of tests on Hefei clays and Chaohu clays showed thatthe values of p_c obtained by this method are in good agreement with the true value of p_c.