目的　探讨小脑后下动脉瘤的影像学特征及外科治疗方案。方法　回顾性分析 5例小脑后下动脉瘤的临床特点、影像学特征及手术治疗效果。结果　 5例中有 4例因动脉瘤破裂出血而发病 ,CT检查均有第Ⅳ脑室出血 ;1例首发症状为步态不稳及后组颅神经不全性麻痹 ,经CT检查为后颅窝占位性病变。DSA检查可显示动脉瘤的具体部位及大小。 5例均经后颅窝开颅显微手术治疗 ,其中动脉瘤蒂夹闭 3例 ,行动脉瘤加固术及孤立术各 1例。 5例中除 1例术后留有轻度偏瘫外 ,余 4例恢复良好。结论　小脑后下动脉瘤多以第Ⅳ脑室出血发病 ,少数可以小脑及后组颅神经损害为首发症状 ,及早诊断和治疗 ,疗效是满意的。手术方式应尽量夹闭动脉瘤蒂 ,对夹层动脉瘤可采用加固术 ,少数无法夹闭瘤蒂者则行动脉瘤孤立术 Objective To investigate the imaging features and surgical treatment of posterior inferior cerebellar aneurysms. Methods A retrospective analysis of 5 cases of posterior inferior cerebellar aneurysm clinical features, imaging features and surgical treatment. Results 4 of 5 cases were diagnosed as having aneurysm rupture and hemorrhage occurred in CT examination. The first symptom of one case was unstable gait and the posterior cranial nerve incomplete paralysis. CT examination showed posterior fossa Bisexual lesions. DSA examination can show the specific location and size of the aneurysm. 5 cases were treated by posterior fossa craniotomy microsurgery, including 3 cases of aneurysm pedicle clamp, aneurysm aneurysm surgery and ligation in 1 case. In 5 cases, except 1 case left with mild hemiplegia, the other 4 cases recovered well. Conclusion Most of the posterior inferior cerebellar aneurysms have the incidence of IV ventricular hemorrhage. A few of them may be the first symptom of cerebellar and posterior cranial nerve damage. Early diagnosis and treatment are satisfactory. Surgical approach should be closed aneurysm pedicle, dissection can be used for dissecting aneurysm, a few can not clip pedicle aneurysm is aneurysm surgery