  In this paper, we have studied biharmonic hypersurfaces in space form
$\bar{M}^{n+1}(c)$ with constant sectional curvature $c$. We have obtained that
biharmonic hypersurfaces $M^{n}$ with at most three distinct principal
curvatures in $\bar{M}^{n+1}(c)$ has constant mean curvature. We also obtain
the full classification of biharmonic hypersurfaces with at most three distinct
principal curvatures in arbitrary dimension space form $\bar{M}^{n+1}(c)$.
