We consider a mass-critical system of nonlinear Schödinger equations i∂tu + ∆u =ūv,valued unknown function and κ > 0 is a constant. If κ = 1/2, we say the equation satisfies mass-resonance condition. We are interested in the scattering problem of this equation under the condition M (u, v) < M (φ, ψ), where M (u, v) denotes the mass and (φ, ψ) is a ground state. In the mass-resonance case, we prove scattering by the argument of Dodson [5].