In this study, we tried to find a safe as well as fast effective treatment for sedation and analgesia for intrathecal injection in childhood leukemia patients, relieving treatment difficulties and pain, increasing the success rate of single intrathecal injection.The patients were divided into the experimental group (fentanyl combined with etomidate) and the control group (lidocaine only) randomly. The experimental group was given fentanyl 1 to 2 μg/kg intravenously first, then etomidate 0.1 to 0.3 mg/kg intravenously after the pipe washed. The patients younger than 1.5 years or who did not achieve satisfied sedative and analgesic situation received an additional time of etomidate (0.1-0.3 mg/kg). The patients were given oxygen at the rate of 4-5 L/min during the whole operation, and the finger pulse oximeter was used simultaneously to detect the changes in heart rate (HR) and blood oxygen saturation (SpO2). The doctors who performed the procedures assessed the quality of sedation and analgesia.In the experimental group, the patients' HR increased slightly after given fentanyl combined with etomidate. The patients' SpO2 was stable. Most patients achieved a good sedative and analgesic state within 1 to 2 minutes, and no case of respiration depression or cardiac arrhythmias occurred during the whole operation. The wake-up time was 55.42 ± 20.62 min. In the control group, the patients were not very cooperative during the intrathecal injection, which made the procedures very difficult.During intrathecal injection, pain obviously reduced and the success rate of single lumbar puncture increased. It is safe and effective to apply fentanyl combined with etomidate for sedation and analgesia.