Let C be an (n + 2)-angulated category with shift functor Σ and X be a cluster-tilting subcategory of C . Then we show that the quotient category C /X is an n-abelian category.If C has a Serre functor, then C /X is equivalent to an n-cluster tilting subcategory of an abelian category mod(Σ −1 X ). Moreover, we also prove that mod(Σ −1 X ) is Gorenstein of Gorenstein dimension at most n. As an application, we generalize recent results of Jacobsen-Jørgensen and Koenig-Zhu.Definition 1.1. Let C be an (n + 2)-angulated category with an autoequivalence Σ and X an additive subcategory of C . X is called cluster-tilting if (1) Hom C (X , ΣX ) = 0.(2) For any object C ∈ C , there exists an (n + 2)-angleAn object X is called cluster-tilting in the sense of Opperman-Thomas [OT, Definition 5.3] if add(X) is clsuter-tilting.Recently, Jacobsen-Jørgensen showed that the following result, which was obtained in a special case in the first part of [OT, Theorem 5.6].Theorem 1.2. [JJ, Theorem 0.6] Let C be a k-linear Hom-finite (n + 2)-angulated category with split idempotents, where k is an algebraically closed field and n is a positive integer.Assume that C has a Serre functor S, that is, an autoequivlence for which there are natural equivalenceswhere D(−) = Hom k (−, k) is the k-linear duality functor and Y, Z ∈ C . Assume that X is a cluster tilting object in C with Γ = End C (X). Then