Abstract: The ultimate bearing capacity of jacked pile increases with the time in hyperbolically pattern. The mechanism of time effect can be interpreted as the effect of disturb-restore property and the effect of consolidation of the soil around the pile. Time is adopted to analyze excess pore water pressure due to driven pile in clay; and a formula is derived. According to the original construction force and considering fuzzy and uncertain, we can calculate the final bearing capacity of the pile. Acalculating method is given.