A compact model for the description of ultra-short pulse driven X-ray lasers in Li-like ions is established. Initial electron density, electron temperature and distribution of plasma of the fibre forget irradiated by ultra-short pulses have been related to the intensity and pulse duration of driving lasers and fibre radius.Evolution of Li-like aluminum ion Xray laser gains with time is investigated as well as peak gain dependencies upon the drivinglaser pulse intensity and the duration and fibre radius.