Background <p>Thermal control is pivotal for preventing ureter thermal injury during laser lithotripsy; however, patient-based studies have rarely addressed this topic. In recent years, we have employed a ureter catheter for irrigation drainage and measured temperature changes during lithotripsy. The aim of this study was to evaluate the thermal control effect of this strategy in ureteroscopic holmium laser lithotripsy.</p> Methods <p>From September 2022 to June 2024, patients who underwent ureteroscopic holmium laser lithotripsy at our centre were included in this retrospective cohort study. Patients were divided into a drainage group and a conventional group depending on whether a ureter catheter was used for concomitant drainage during lithotripsy. The temperature was measured using a K-type thermocouple thermometer. Lithotripsy was performed at an irrigation pressure setting of 30 mmHg and a laser setting of 1.0&#xa0;J × 20&#xa0;Hz. Intraoperative and follow-up data were compared between the groups.</p> Results <p>Sixty-seven patients were included, including 32 in the drainage group and 35 in the conventional group. lgCEM₄₃ and the peak temperature of irrigation were significantly lower in the drainage group. The longest continuous lasing time was longer and the operation time was shorter than those in the drainage group. Compared with that in the conventional group, the quality of endoscopic vision in the drainage group during lithotripsy was significantly improved. There was no significant difference in the post-ureteroscopic lesion scale score or the 1-month stone-free rate between the groups. At the 6-month follow-up, no postoperative ureter stricture was observed in either group.</p> Conclusions <p>The current thermal control strategy is safe and feasible; it significantly reduces the intraoperative irrigation temperature and improves endoscopic vision in ureteroscopic laser lithotripsy.</p>