Objective:To investigate the effects of different analgesic methods of hydromorphone on analgesic efficacy and sleep quality in patients with refractory cancer pain.Methods:Sixty patients with refractory cancer pain who received three-step analgesic treatment in Quzhou People's Hospital from August 2018 to December 2019 and acquired poor analgesic effects were included in this study. They were randomly assigned to undergo either an intravenous patient-controlled analgesia with hydromorphone (HV group, n = 30) or an intrathecal patient-controlled analgesia with hydromorphone (HI group, n = 30) for 10 consecutive days. The analgesic efficacy in each group was evaluated using the numerical rating scale (NRS) before and 2, 4, 24, 48 hours, and 10 days after administration. The frequency of breakthrough pain (BTP) at each time point was recorded. The sedation effect of medication was evaluated using the Ramsay score. The sleep quality of patients was evaluated using the Pittsburgh sleep quality index (PSQI). The activities of CD 3+, CD 4+, and CD 4+/CD 8+ lymphocyte subsets were measured by flow cytometry at different time points. The adverse reactions within 10 days after treatment were observed and recorded. Results:Before and at each time point after treatment, there were no significant differences in NRS score, the frequency of BTP, Ramsay score, and PSQI score between the two groups (NRS score: t = 0.45, 0.91, 0.52, 1.19, 0.97, 1.92, all P > 0.05; frequency of BTP: t = 0.34, 1.88, 0.86, 1.71, 1.22, 0.76, all P > 0.05; Ramsay score: t = 0.56, 0.46, 0.63, 0.22, 0.99, 0.14, all P > 0.05; PSQI: t = 0.86, 1.25, 1.46, 1.05, 0.57, 1.93, all P > 0.05). At each time point after treatment, the activities of CD 3+, CD 4+, and CD 4+/CD 8+ cells increased in each group, and the activities of CD 3+, CD 4+, and CD 4+/CD 8+ cells in the HI group were significantly higher than those in the HV group (CD 3+: t = 3.72, 3.12, 2.85, 3.13, 2.44, all P < 0.05; CD 4+: t = 3.62, 2.45, 3.31, 3.19, 2.70; all P > 0.05; CD 4+/CD 8+: t = 3.10, 2.74, 2.83, 3.24, 3.41, all P < 0.05). The total incidence of adverse reactions was slightly, but not significantly, lower in the HI group than the HV group [14.00% (7/30) vs. 26.00% (13/30), χ2 = 2.70, P = 0.100]. Conclusion:Compared with intravenous administration of hydromorphone, intrathecal administration of hydromorphone can better effectively relieve pain, decrease the frequency of BTP, improve sleep quality, has a good sedative effect, improve immune function, and has fewer adverse reactions.