To solve the problem of reliability assessment of life-saving ejection seat of fighter plane, inheritance factor is adopted to describe the similarity between the test data of subsystems of life-saving ejection seat of fighter plane and that of the whole seat. A Bayesian reliability assessment method for life-saving ejection seat of fighter plane based on inheritance factor is put forward. The method combines the reliability information of whole seat and its subsystems using inheritance factor. With the new method, the reliability of a life-saving ejection seat of fighter plane is evaluated and it reaches 0.954 under the confidence level 0.90. The result shows that it is more rational with new method than with classical statistical method and it is feasible to use the new method to evaluate the reliability of life-saving ejection seat of fighter plane.