Abstract: On the basis of analyzing differential of multi-output Boole function, by using the differential characteristics of multi-output Boole function, it was proved that multi-output Boole function f(x) is a orthomorphic permutation if and only if δ_f(α,α)=δ_f(0,α)=0(α≠0). The results showed that the differential table of orthomorphic permutation has the following characteristics: (1) The sum of the elements of each row and column is 2ⁿ; (2) Except δ_f(0,0)=2ⁿ, all the other elements on the first row, first column and diagonal equal to zero