Abstract: After friction welding, the drill pipe weld needs to be quenched-tempered heat treatment.The abnormal tempering microstructure generated during quenched-tempered heat treatment processing will affect the quality of drill pipe seriously.The cause of abnormal microstructure, distribution and effect on final quality were analyzed in detail.At the same time, the prevention advices and suggestions were raised.The problems caused by abnormal tempering structure could be solved through improve the quality of drill pipe weld surface and the equipment position stability, and install temperature alarm sensor.