Titanium alloys have a dwell fatigue failure mode during service in the aircraft engine, which is manifested by a significant reduction in fatigue life when comparing with normal continuous cycling. In contrast to normal fatigue, dwell fatigue has distinct failure characteristics. Through a systematic experimental research, this paper summarized the characteristics of dwell fatigue failure from three aspects, including the fatigue fracture, secondary crack and strain accumulation. The research objects covered from highly susceptible to unsusceptible titanium alloys. According to the summarized failure characteristics, a methodology for identifying the dwell fatigue failure and assessing the dwell sensitivity has been given, which could provide guidance for the experimental research and engineering failure investigation.