Abstract: The test duration of composites is highly dependent on the accuracy required for load enhancement factor (LEF) in accelerated test methods to verify the durability of aircraft composite structures. The T300/BPM316 composite laminate with the layer mode for 45/-45/0/0/-45/90/0/90/45/0_s is studied in this paper. The fatigue life scatter of composites is analyzed by modified joint Weibull distribution, and MATLAB software is used, based on which the load enhancement factor is calculated. The results show that the LEF of T300/BMP316 composites laminates decreased when the test duration is increased; while the influence of test number is very small on the reliability of durability test, and its influence on the load enhancement factor can be ignored. The combined load enhancement factor method is validated by using modified joint Weibull distribution to analyze the fatigue life of composite material scatter, and it is not affected by the original load enhancement factor, which demonstrates its potential wide application.