Abstract: Objective To determine the feasibility and clinical efficacy of ultrasound-guided facet joint injection and nerve block in lumbar facet joint for the treatment of facet-joint related low back pain. Methods 20 patients with facet-joint pain were randomized into two groups received block blindly（B group) or guided by ultrasound (US group) respectively. The location of needle tip was confirmed by CT in both groups, and the accuracy was computed afterwards. VAS score, puncture time and one-time puncture success rate（%) were recorded. VAS scores and pain remission rates in both groups were recorded at 30 min, 1 d, 2 d, 6 weeks after the block. Results The VAS scores were 3.3±0.4 in US group and 1.2±0.3 in B group (P<0.05). The puncture time was (206±27) s in US group while (397±31) s in B group (P<0.05). There were 37 facet joint blocks guided by ultrasound, in which 32 were correctly targeted with the first puncture. The success rate is 86.5%. There were 35 facet joint blocks blindly, in which 11 were correctly targeted with the first puncture. The success rate is 31.4%. The difference of one-time puncture success rate between the two groups was significant (P<0.05). Differences of VAS and pain remission rate at half an hour after facet joint injection between B group and US group were significant (P<0.05). There were 8， 9， 9, and 9 patients in US group obtaining a reduction in VAS scores≥3 at 30 min, 1 d, 2 d and 6 weeks after the procedure respectively, while the numbers of such patients were 5, 6, 5, 5 in B group (P>0.05). After 6 weeks of follow-up, the overall remission rates were (72.3±14.0)% in US group, and (56.7±11.0)% in B group, there was no significant difference between the two groups (P>0.05). Conclusion The ultrasound-guided lumbar facet joint injection technique had a high feasibility and accuracy, and had better clinical efficacy than block blindly.