We construct explicitly the q-vertex operators (intertwining operators) for the level one modules V (Λi) of the classical quantum affine algebras of twisted types using interacting bosons, where i = 0, 1 for A (2) 2n−1, i = 0 for D (3) 4 , i = 0, n for D (2) n+1, and i = n for A (2) 2n . A perfect crystal graph for D (3) 4 is constructed as a by-product.