By using an inequality relation between a scalar curvature and the length of the secondfundamentalform, it is proved that sectional curvatures of a submanifold must be nonnegative (or positive).
Moebius secondfundamentalform is important Moebills invariable on the unit sphere of submanifolds, in this paper, we classify the surface in s ~ 3 with semi-parallel Moebius secondfundamentalform.