Objective: To evaluate the effect of preemptive analgesia with hydromorphone in thoracoscopic lobectomy and its effect on the rapid recovery of patients after surgery. Methods: From November 2021 to November 2022, 60 patients undergoing thoracoscopic lobectomy in our hospital were randomly divided into two groups, with 30 patients in each group, namely the control group and the ERAS group, 0.9 % normal saline 5 mL and 15 μg/kg hydromorphone were injected intravenously at the time of skin incision and 30 min before the end of operation, respectively. The mean arterial pressure (MAP) of the two groups at 5 min after entering the operating room (T1), at the time of skin incision (T2), 30 min after extubation (T3), 6 h after extubation (T4) and 72 h after extubation (T5); serum concentrations of substance P (SP), neuropeptide Y (NPY) and prostaglandin E2 (PGE2) were measured at T1 and T4; the VAS pain scores at 30 min (T3), 6 h (T4) and 72 h (T5) after intubation; the postoperative length of stay (LOS) of the two groups was compared. Results: (1)There were no significant differences between the two groups in genders, ages, BMI, operation duration, intraoperative bleeding and ASA grades (P＞0.05). (2)There were no statistically significant differences in MAP at T1, T2, T3, T4 and T5 in ERAS group (P＞0.05), while the MAP at T4 in control group was higher than those at T1, T2, T3 and T5, and the MAP at T5 were higher than that at T1, the difference was statistically significant (P＜0.05); the MAP of the control group at T2, T3, T4 and T5 was higher than that of the ERAS group, the difference was statistically significant (P＜0.05); there was no significant difference in concentrations of SP, NPY and PGE2 at T1 between the control group and ERAS group (P＞0.05); the concentrations of SP, NPY and PGE2 at T4 in control group and ERAS group were higher than those of T1, the difference was statistically significant (P＜0.05); the concentrations of SP, NPY and PGE2 at T4 in the control group were higher than those in the ERAS group, and the difference was statistically significant (P＜0.05); there were no statistically significant differences in VAS scores at T3, T4 and T5 in ERAS group (P＞0.05), while the VAS scores at T4 in control group were higher than those at T3 and T5 (P＜0.05); the VAS scores at T3, T4 and T5 in the control group were significantly higher than those of the ERAS group (P＜0.05); There was a statistically significant difference in LOS between the control group and the ERAS group (P＜0.05). Conclusion: Intravenous injection of 15 ug/kg hydromorphone before and 30 minutes before the operation of thoracoscopic lobectomy can ensure hemodynamic stability and effective postoperative analgesia, reduce inflammatory reaction, and also reduce postoperative hospital stay, thus saving medical costs, hospital expenses and improving quality of life.