Objective: To investigate the effective dosage and safety of esketamine combined with different doses of propofol for painless abortion. Methods: A total of 88 young female patients aged 18 to 40 years who were scheduled for painless induced abortion were randomly assigned to receive 1.5 mg/kg, 2.0 mg/kg, or 2.5 mg/kg propofol according to the sequential method,and were sequentially given different doses of esketamine.Esketamine required by 50% of patients to respond to the motor stimulation of surgery was calculated. The patients' heart rate (HR), mean arterial pressure (MAP), and pulse oxygen saturation (SpO2) were continuously monitored during anesthesia, and data on anesthesia and recovery time, as well as perioperative adverse reactions, were recorded. Results: ①The ED50 of esketamine in the three groups decreased successively(p<0.01), which were 0.320(0.281-0.364), 0.244(0.207-0.291) and 0.167(0.078-0.320), respectively.② The HR of T1 in 2.5mg/kg propofol group was significantly decreased compared with T0 (p<0.05), but there was no significant difference between the other two groups. The MAP of T1 in 2mg/kg and 2.5mg/kg propofol groups was significantly lower than that in T0 group (p<0.05), and the MAP in 2.5mg/kg propofol group was significantly lower than that in 1.5mg/kg group (p< 0.0167);③ There were significant differences in recovery room retention time among all groups (p<0.05);④ There were significant differences in the incidence of hypotension and respiratory depression in 2.5mg/kg propofol group (p<0.05). The incidence of choking and headache after recovery in 1.5mg/kg propofol group was significantly higher than that in the other two groups (p < 0.05). Conclusion: In young female patients undergoing painless induced abortion, the anesthesia scheme of 2.0 mg/kg propofol combined with ketamine had the best overall effect, with the ED50 and ED95 of ketamine being 0.214 (0.195-0.236) mg/kg and 0.334 (0.282-0.557) mg/kg, respectively.