The differences of negative skin friction（NSF） character between pile with working load and without working load are compared.It is pointed out that neutral point of pile is the lowermost

and downdrag caused by NSF is maximal taking no account of working load on pile.Analysis shows that neutral point of pile with working load is much higher than that of pile without working load

downdrag with working load is smaller than that without working load evidently.Furthermore

neutral point moves upwards obviously as working load increasing

the downdrag decreases obviously as working load increasing.The influence of NSF on pile settlement is almost linear while working load is small.Shift of neutral point and change of downdrag are smaller in longer pile than that in shorter pile while working loads act.It may be useful to the research of negative skin friction characters of pile.