The traditional load enhancement factor (LEF) method was derived from the composite static strength and fatigue life Weibull distribution. In order to ensure the reliability of composite fatigue verification test and a smaller dispersion of load enhancement factor, the fatigue reliability theory was used to derived a new load enhancement factor method based on composite fatigue strength and fatigue life Weibull distribution. This new method is called fatigue strength load enhancement factor (FLEF) method. The LEF and FLEF methods were applied to the analysis of fatigue test data. The results show that the LEF could not guarantee the reliability of composite fatigue verification without batch data and the FLEF has smaller dispersion and higher reliability. It is concluded that compared with the LEF method, the FLEF method is more suitable to determine the load enhancement factor in theory and practice.