Objective To investigate the efficacy and safety of CT-guided radioactive 125I seed implantation(ISI)for blocking celiac plexus in the treatment of refractory abdominal cancerous pain.Methods The clinical data of 60 patients with refractory cancerous pain caused by abdominal malignancies(visual analogue scale score ≥4 points)were retrospectively analyzed.Patients of group A(n=29)received anhydrous ethanol injection treatment and patients of group B(n=29)received ISI treatment.The primary endpoints were pain score(visual analogue scale,VAS),daily morphine consumption(DMC),and local tumor control(LTC)rate.Secondary endpoints included the success rate of the procedure and postoperative complications.Results The technical success rate of surgery was 100％in both groups,and no serious complications occurred after surgery.The VAS pain scores in both groups showed a continuous decline from 1 to 8 weeks after surgery,but the difference was not statistically significant.However,the VAS scores in group A was significantly increased at T8 to T12 weeks(P＜0.01).In contrast,the pain relief time in group B remained stable until T16 to T24 weeks when an increase in pain improvement was observed.At T8 week,the LTC rate in group B was significantly better than that in group A,and the difference was statistically significant(P＜0.01).Conclusion Celiac plexus block with ISI can effectively alleviate the refractory cancerous pain caused by abdominal tumors.Compared with anhydrous ethanol injection,ISI has a longer pain relief time(up to T16-T24 weeks)and can effectively control the growth of local tumor,which is worthy of clinical promotion and application.