Harms technique of C1-C2 fixation for atlantoaxial complex becomes more popular due to good fusion rate and low vertebral artery injury (VAI) rate.But considering the unique and variable anatomy of atlantoaxial complex,iatrogenic VAI will result in catastrophic consequences and provides particular surgical challenges for surgeons.To our knowledge,comparing with iatrogenic VAI in the screw hole,iatrogenic VAI in the open space is much rarer during the Harms technique of C1-C2 fixation.In this article,we present a case of iatrogenic vertebral artery pseudoaneurysm after Harms technique of posterior C1-C2 fixation.This case of iatrogenic VAI effectively treated by endovascular coil occlusion and extal local compression was initially misdiagnosed as VAI by pedicle screw perforation.It can be concluded that intraoperative or postoperative computed angiography is very helpful to diagnose the exact site of VAI and the combination of endovascular coil occlusion as well as extal local compression can further prevent bleeding and abnormal vertebral artery flow in the pseudoaneurysm.However,patients treated require further follow-up to confirm that there is no recurrence of the pseudoaneurysm.