The middle route of the South to North Water Transfer Project(SNWTP) is being constructed in China. The canal of SNWTP will traverse across the Yellow River. At the north floodplain of the river the canal will be established on a sandy ground for about 6 500 m in length. To estimate the liquefaction possibility of the foundation under earthquake, a standard penetration test has been carried out. Sixteen tested holes were sparsely distributed in the length of 6 500 m, so much difficulty may exist in judging the possible lique faction range for the whole foundation. In this situation, interpolation computation between tested holes should be employed. The Krigings interpolation method, which has been widely applied in geography, was introduced and adopted in this foundation. Based on the interpolation, the liquefaction depth and span of thecanal foundation were analyzed and discussed. The research effort in this paper shows a bright application prospects of the Krigings interpolation method in geotechnical investigation. 