Under the typical parameter conditions of laser-produced plasma, thepopulation inversion-ratio values and gain coefficients for transitions 5f-3d and 4f-3din Li-like silicon ion are calculated by using the collisional-radiative model. We havediscussed the effects of different thermal band selections and cooling velocity on thecalctilated laser gain c,JefficientS. The calculated resultS show that, when the temperatureof the hot plasma is very rapidly lowered after the short driving laser pulse, there are gains in the 4f-3d and 5f-3d transitions.