A port project in Namibia was built on diatomaceous soil more than 20 meters thick,thus the settlement of the foundation caused by backfilling in the rear land area brings serious negative friction problems to the pile foundation of the wharf.Aiming at the problem of negative friction in this project,the relevant clauses of the European Standard Code are studied and the bearing capacity of pile foundation under the influence of negative friction is calculated.The varieties of engineering countermeasures are proposed to reduce the adverse effect of negative friction,such as delaying the construction time of pile foundation,driving steel casing through diatomaceous soil layer,increasing the diameter of pile，increasing penetration depth and enlarging pile base.Among these measurements,delaying the construction time is the lowest comprehensive cost solution.The calculation method adopted in this paper can provide a reference for the negative friction calculation of pile foundation in similar foundation.