Abstract: Laser ablation in liquid can modify the target morphology, as well as fabricate micro-nano materials in the solution. Many researchers were attracted by this method, because it was chemically clean, low cost and simple operation. Here, germanium particles with micron and submicron scale were prepared by Nd: YAG nanosecond pulsed laser ablation in water. The characteristics of germanium particles were studied by ultraviolet-visible absorption spectrum (uv-vis), X-ray diffraction (XRD) and scanning electron microscope (SEM). Then, studied the target morphology and ablation quality were studued after laser ablation of the germanium target. It was found that the ablation quality increases with the number of laser pulses, but the increase rate decreases, which means the ablation efficiency decreases. Finally, the reasons for the decrease of ablation efficiency were discussed to provide theoretical reference and feasible strategy for improving the preparation rate of materials fabricated by laser ablation in liquid.