[en] The production of GWs during preheating in the Starobinsky model with a nonminimally coupled auxiliary scalar field is studied through the lattice simulation in this paper. We find that the GW spectrum Ω${}_{gw}$ grows fast with the increase of the absolute value of coupling parameter ξ. This is because the resonant bands become broad with the increase of |ξ|. When ξ<0, Ω${}_{gw}$ begins to grow once the inflation ends and grows faster than the case of ξ>0. Ω${}_{gw}$ reaches the maximum at ξ=−20 (ξ=42 for the case ξ>0) and then decreases with slight oscillation. Furthermore we find that the GWs produced in the era of preheating satisfy the limits from the Planck and next-generation CMB experiments.