The long uplift piles are researched in this paper through the comparative analysis of conventional straight piles, grouting piles and under-reamed piles. The theoretical equation of load-displacement is derived by a mathematical model. The mechanism of increasing load-carrying capacity and load transfer law of the different piles are studied by analysising the load-carrying capacity when the displacement of the pile top is 30 mm, and the distribution of frictional resistances of different style of piles in a mollisol area of coastal. The grouting straight piles should be the priority selection because of the increase of safety probability.