In this paper, we are concerned with the Cauchy problem for 3D incompressible Navier-Stokes-Cahn-Hilliard equations. First, applying a refined pure energy method, assuming u 0 H 1 + φ 0 H 1 + ∇φ 0 H 1 is sufficiently small, we obtain the global well-posedness of solutions. Moreover, the optimal decay rates of the higher-order spatial derivatives of the solution are obtained, the Ḣ−s (0 ≤ s ≤ 1 2 ) negative Sobolev norms is shown to be preserved along time evolution and enhance the decay rates.