Suppose M and N are von Neumann algebras. Two operators A and B in M are said to be orthogonal if A*B = 0, meaning their ranges are orthogonal. Let ϕ: M → N be a map. We say ϕ is an ortho-isomorphism if it is bijective and satisfies A∗B = 0 if and only if ϕ(A)∗ϕ(B) = 0 for any A, B ∈ M . The map ϕ is called ortho-additive if for any A, B ∈ M with A∗B = 0, it holds that ϕ(A + B) = ϕ(A) + ϕ(B). In this paper, we characterize the complete structure of ortho-additive ortho-isomorphisms between von Neumann algebras，which is an analogue of Dye’s theorem and Uhlhorn’s theorem.