观察并分析了碳钢盘条拉伸异常断口的宏观形貌为舌形灰色（或黑色）区域纤维状断口，其余为发亮结晶状断口。前者微观形貌为延性韧窝特征，后者微观形貌为脆性解理特征。讨论盘条拉伸异常断裂行为与其显微组织及拉伸速度的关系。认为拉伸异常断口的形成主要取决于其显微组织中的珠光体分布特征，其次与拉伸速度有关。 The macroscopic appearance of abnormal tensile fracture of carbon steel wire rod was observed and analyzed as the fibrous fracture of tongue gray (or black) region, and the rest was shiny crystalline fracture. The former micro-morphology ductile dimples feature, the latter micro-morphology brittle cleavage features. The relationship between abnormal tensile behavior of wire rod and its microstructure and tensile velocity was discussed. It is considered that the formation of abnormal tensile fracture mainly depends on the distribution of pearlite in the microstructure, and secondly the tensile velocity.