Objective To investigate the clinical benefits of CT-guided interstitial iodine-125 seed implantation in the treatment of metastatic or primary spinal and paraspinal tumors.Methods 38 patients (with43 lesions) of metastatic or primary spinal and paraspinal tumors, with no surgery or external beam radiotherapy opportunity, were underwent implantation procedure.Treatment planning system (TPS)was used to formulate the seeds distribution and assess radiation dosimetry preoperation and to obtain quality evaluation postoperation.Needles placement under CT-guidance were performed according to TPS.The mean minimal peripheral doses of implantation was 120Gy (ranged from90-140Gy).The mean number of seeds was 79 (ranged from 10-224), The mean specific activity per seed was mCi 0.7 (ranged from 0.50-0.80 mCi).Visual analogue scale (VAS) and Ambulatory function score (AFS) was used to evaluate pain relief and limb function.Results All patients tolerated the procedures well.No complications occurred.The mean follow-up was 15.3 months(ranged from 1 to 96 months).The local control rate was 76.3% (29/38).The mean local control time and survival time was 14.2 months and 15.3 months.The 1-, 2-, 3-, and 5-year local controls were 72.2%, 72.2%, 72.2% and 72.2%, respectively.The 1-, 2-, 3-, and 5-year survival rates were64.1%, 33.0%, 19.8% and 13.2%, respectively.The mean VAS pre-and postoperation was5.32±2.30 and 1.34±1.81, respectively (P<0.001).Response rate of limb function were 71.0%(22/31).Conclusion CT-guided interstitial iodine-125 seed implantation as a promising local therapy and salvage treatment of metastatic or primary spinal and paraspinal tumors is safe,minimally invasive and high efficacy.