Abstract: Using actual data in typical intensive formation flying,the variance between different aero-engines in almost the same flying conditions was researched.Aero-engine fatigue variance and its statistical rules due to different positions of the chief and the wing aircraft can be elicited,after the data were converted to the standard cycle by quadratic rainflow counting algorithm and the Miner damage accumulation.It is found that it accords with Weibull distribution,namely,single aircraft variance can reach 2～4 times and the maximal variance can reach 9～10 times because of the same reason.Furthermore,the variance of aero-engine fatigue load/damage and the necessity of single aircraft life monitoring are revealed.