Abstract: The sinking process of the shaft foundation under a bridge pier in Haiko has been monitored. According to the observed field data, the penetration mechanism and resistance characteristic in sinking process are systematically studied. The distribution of wall side friction and end bearing, daring penetrating into differ ent soil strata is obtained. The computing method and experimental formula of sinking coefficient K, and the value of side frictionσf, as well as reference value of earth pressure, are put forward. Then, the computation model of penetration resistance is established. The calculation formula and distribution characteristic of the maximum side friction f0 is submitted. The conclusions obtained in this paper can be used for reference of other engineering project.