We consider the final-state problem for the nonlinear Schrödinger equations (NLS) with a suitable time-decaying harmonic oscillator. In this equation, the power of nonlinearity |u| ρ u is included in the long-range class if 0 < ρ ≤ 2/(n(1 − λ)) with 0 ≤ λ < 1/2, which is determined by the harmonic potential and a coefficient of Laplacian. In this paper, we find the final state for this system and obtain the decay estimate for asymptotics.