Abstract: Objective:To evaluate the efficacy and safety of continuous intrathecal morphine infusion system for patients with refracto -ry cancer pain. Methods:Seventeen patients with refractory cancer pain were implanted with intrathecal catheters and connected with a continuous external electronic patient- controlled analgesia (PCA) pump for intrathecal morphine analgesia. Visual analogue scales (VAS) score, the dose of routine opioids, and the score for quality of life before and after intrathecal analgesia were recorded. Adverse reactions were observed. Results: After the application of continuous intrathecal morphine analgesia, the VAS score of pain was 2. 9 ± 1. 8, which is lower than 7. 2 ± 2. 5 before intrathecal analgesia ( P<0. 001 ). Moreover, the dose of routine opioids (i.e., equianal-gesic dose of morphine) was 42. 1 ± 7. 5 mg/day, which is significantly lower than 282 . 9 ± 95. 5 mg/day before intrathecal analgesia (P=0. 004 ). The scores of general activity, mood, and sleep after intrathecal analgesia were significantly lower than those before intrathe-cal analgesia ( P<0. 05). However, the analgesic satisfaction of patients considerably increased after intrathecal analgesia ( P<0. 001 ). Ad -verse reactions included withdrawal syndrome, headache, urinary retention, and intrathecal infection. Conclusion: The continuous in-trathecal morphine infusion with PCA is effective and safe on analgesic treatment for patients with refractory cancer pain.