Unlike women undergoing period selective cesarean deliveries, women who converted to cesarean deliveries from vaginal deliveries not only face urgent labor abnormalities, but also may be suffering from high‑risk factors for abnormal extensive neuraxial block. So it is particularly important to prevent and manage abnormal diffusion of the block plane. Although the occurrence of abnormal extensive neuraxial block is relatively rare, it tends to change rapidly and is a kind of critical condition. This article reports a case of high neuraxial block after conversion of labor analgesia to cesarean delivery. The common causes, differential diagnosis, and precautions for abnormal spread of the neuraxial block are presented in discussion.