Abstract: Preconsolidation pressure is an index of deciding the stress history of a soil layer, and is also an important computation parameter in settlement analysis dealing with soils which have different stress histories. It is very significant to determine preconsolidation pressure conveniently and precisely. Experimental investigation was proceeded for preconsolidation pressure determining in scientific research item of north concrete anchor of Ruyang bridge and preconsolidation pressure value is computed through MATLAB programme.