Pile bottom post grouting for friction pile with super long (＞100m) and super large（φ2.5m）was first applied in loose and soft formation in Sutong Bridge construction in China. Based on the engineering practice, the design and key technical points were introduced. By the analysis on the samples, the obvious difference of slurry initial setting time between ground experiment and underground situation was found. According to the slurry diffusion and permeation conditions by sampling, the grouting amount, not the pressure, is taken as control parameter in permeable formation.