We consider the final-state problem for the nonlinear Schr\"{o}dinger equations (NLS) with a suitable time-decaying harmonic oscillator. In this equation, the power of nonlinearity \(|u|^{\rho}u \) is included in the long-range class if \(0 < \rho \leq 2/(n(1- \lambda)) \) with \(0 \leq \lambda <1/2\), 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.