In order to improve the efficiency of Holmium laser lithotripsy and reduce the operation time, the influence of the peak power of Holmium laser pulse, optical fiber core diameter and working distance on the efficiency of Holmium laser ablation was investigated. First, an in vitro model device was built to simulate the process of Holmium laser lithotripsy in the ureter. In the experiment, a 250mg cube plaster model was used to replace human stones. Then, the parameters required for the experiment were determined. The optical power of the Holmium laser was 10W, 12W, 20W and 24W, pulse duration is 200μs and 800μs. Optical fiber uses fiber of core diameter of 272μm and 550μm, working distance is from 0mm to 4mm. The results show that the Holmium laser ablation efficiency increases with the increase of the pulse peak power. When the pulse energy is 2J, the Holmium laser lithotripsy efficiency is the highest at 1.4mg/s and when the pulse energy is 0.5J, the Holmium laser lithotripsy efficiency is the lowest at 0.1667mg/s. Short pulse width ablates 35.72~86.68% more calculus quality than long pulse width. Fiber core diameter does not affect the ablation efficiency significantly. As the working distance increases, the ablation efficiency will decrease. The laser will not ablate when the distance from the stone model is 3mm. The experimental results will be useful for clinical treatment and refined of domestic Holmium laser parameters.