Experiments of soft X-ray amplified-spontareous-emission (ASE) based on recombination pumping scheme were successfully performed on the Six-beam high power Nd3+-glass laser facility of SIOM, Using a home-made pinhole transmission grating speotrography, ASE has been observed in Li-like Al+10 ions 4f-3d(154.7 A) transition in plasmas produced by irradiation of slab aluminum targets With line-focused laser light. Time integrated intensities of Li-like Al+10 ion spectral lines emitting along the axis of the plasmas were measured for a set of different plasma lengths. It is shown that the intensities of spectral lines of Li-like Al+10 4f-3d transition increase exponentially with increasing plasma lengths, and the correspon ding gain coefficient is 3.7±0.9cm-1. The maximum gain-length product being about 2.7.