In this talk we will discuss the singularity profile of the mean curvature flow. We introduced and proved the /kappa-noncollapsing for the mean convex MCF.  The /kappa-noncollapsing implies that a blow-up solution to mean convex MCF is convex. We also proved that there exist non-rotationally symmetric, ancient convex solutions. But in dimension two, a translating blow-up solution must be rotationally convex.