The problem of the description of the orbit space X n = G n,2 /T n for the standard action of the torus T n on a complex Grassmann manifold G n,2 is widely known and it appears in diversity of mathematical questions. A point x ∈ X n is said to be a critical point if the stabilizer of its corresponding orbit is nontrivial. In this paper, the notion of singular points of X n is introduced which opened the new approach to this problem. It is showed that for n > 4 the set of critical points CritX n belongs to our set of singular points SingX n , while the case n = 4 is somewhat special for which SingX 4 ⊂ CritX 4 , but there are critical points which are not singular.The central result of this paper is the construction of the smooth manifold U n with corners, dim U n = dim X n and an explicit description of the projection p n : U n → X n which in the defined sense resolve all singular points of the space X n . Thus, we obtain the description of the orbit space G n,2 /T n combinatorial structure. Moreover, the T n -action on G n,2 is a seminal example of complexity (n − 3) -action. Our results demonstrate the method for general description of orbit spaces for torus actions of positive complexity. 1