We study the Bernstein type problem for complete submanifolds in the space forms. In particular, we prove that any complete super stable minimal submanifolds in an (n + p)-dimensional Euclidean space R n + p (n ≤ 5) with finite L 1 norm of the second fundamental form must be affine n-dimensional planes. We also prove that any complete noncompact weakly stable hypersurfaces in R n + 1 (n ≤ 5) with constant mean curvature and finite L d (d = 1, 2, 3) norm of traceless second fundamental form must be hyperplanes.