The sedimentary clay in the alternate marine and terrigenous environment of the north side of the Yangtze River estuary is possessed of the interbedded structure by interlacing the clay and silt

as well as the granular composition of high silt content. And its physical property indexes are in-consistent with its mechanical property indexes. The principal component analysis of multi-statistic theory is applied to analyze the potential of engineering characteristics through the routine physical indexes. The results indicate that it is not scientific that sandy loam is subjected to clay category; and the methods is not all reasonable estimating physical consistency state of sandy loam with relative water content and inferring its engineering characteristic.