In this paper, we study umbilic-free submanifolds of the unit sphere with parallel Möbius second fundamental form. As one of our main results, we establish a complete classification for such submanifolds under the additional condition of codimension two. Int. J. Math. 2014.25. Downloaded from www.worldscientific.com by MICHIGAN STATE UNIVERSITY on 02/07/15. For personal use only. 1450062-2 Int. J. Math. 2014.25. Downloaded from www.worldscientific.com by MICHIGAN STATE UNIVERSITY on 02/07/15. For personal use only. Submanifolds with parallel Möbius second fundamental form (d) the image of σ of a cone overwhere H n−k ( √ 1 + a 2 ) denotes the (n − k)-dimensional hyperbolic space of constant sectional curvature −1/(1 + a 2 ), and S k (a) denotes the k-dimensional Euclidean sphere of radius a.Remark 1.1. The two maps σ and τ mentioned above are the canonical conformal diffeomorphisms whose definitions are presented in (2.2) and (2.3), respectively. Whereas the notion about "cone" is referred to Definition 3.1.When compared with the hypersurfaces situation, the problem on the classification of higher codimension umbilic-free submanifolds of the unit sphere with parallel Möbius second fundamental form is now still open, which obviously would be much more complicated.In this paper, as our continuous attempts working on the above problem, we made the discovery that the assumption "parallel Möbius second fundamental form" implies that the submanifold is of parallel Blaschke tensor. This latter property plays an important role for us to know further about submanifolds with parallel Möbius second fundamental form. Indeed, as our main result, on the basis of Ferus, Backes-Reckziegel and Takeuchi's classification of (Euclidean) parallel submanifolds in space forms, and by using the particular properties of submanifolds of codimension two, a complete classification of Möbius parallel submanifolds can be established for p = 2 case, which can be stated as follows:Theorem 1.2. Let x : M n → S n+2 be an n-dimensional umbilic-free submanifold with parallel Möbius second fundamental form. Then x is Möbius equivalent to an open part of one of the following submanifolds:(i) an umbilic-free submanifold with parallel second fundamental form in S n+2 , (ii) the image of σ of an umbilic-free submanifold with parallel second fundamental form in the Euclidean space R n+2 , (iii) the image of τ of an umbilic-free submanifold with parallel second fundamental form in the hyperbolic space H n+2 , (iv) the image of σ of a cone over some k-dimensional umbilic-free submanifold with parallel second fundamental form in S k+2 (k ≤ n − 1).Remark 1.2. In above theorem, we made the assumption of codimension two that is used, first of all, in Lemma 5.1 to reduce the distinct number of eigenvalues of A to no more than four. We noticed, which Prof. Xiang Ma also observed and kindly informed us, that in higher codimensional case similar results can still be obtained, but the problem at the moment is that subsequently geometric discussions become much more ...