对Ｑ２３５钢惯性摩擦焊接头进行了超声检测，观察了典型接头包括含缺陷和无缺陷接头的微观组织，并做了拉伸试验和冲击试验。试验证明，碳钢惯性摩擦焊接头的接合面晶粒细小，静强度很高；接合面的缺陷对静强度影响不大，但使接头的冲击韧性大大下降；超声检测用于碳钢惯性摩擦焊接头，能有效地检出缺陷。 The ultrasonic testing of Q235 steel inertial friction welding joint was carried out. The typical joints were observed including the microstructure with defects and defect-free joints, and the tensile test and the impact test were done. Experiments show that the inertia friction welding joints of carbon steel have small grain size and high static strength. The defects on the joint surface have little effect on the static strength, but greatly reduce the impact toughness of the joints. Ultrasonic testing is used for inertial friction welding of carbon steel Head, can effectively detect defects.