Objective Based on construction and verification of the lumbar finite element model, the simulation calculation and injury prediction on dynamic response of normal lumbar model and L5 unilateral and bilateral spondylolysis models of the pilot were carried out, so as to explore the influence of persistent flight overload on normal and spondylolysis lumbar vertebrae of the pilot. Methods The precise finite element model of lumbavertebrae was established using reverse engineering software and computer-aided engineering (CAE) technology based on CT images. The validity of the lumbar vertebrae model was verified by static and dynamic in vitro experiments. The biomechanical simulation analysis on normal and spondylolysis lumbar vertebrae of the pilotunder persistent overload was carried out, and the spinal injury was predicted and analyzed by dynamic response index (DRI) injury evaluation and prediction method. Results The maximum isthmus stress of L5 vertebra in unilateral and bilateral spondylolysis models were 105. 29 MPa and 126. 32 MPa, respectively, which were significantly higher than those in normal model. The L4-5 and L5-S1 intervertebral discs of the spondylolysis model were more prone to premature degenerative changes than those of normal model. Combined with DRI spinal injury prediction method, the probability of spinal injury in normal lumbar vertebrae, lumbar vertebrae with L5 unilateral and bilateral spondylolysis were 0. 001 4% , 2. 26% and 3. 21% , respectively, and the probability of spinal injury was significantly increased after the occurrence of spondylolysis. Conclusions The spondylolysis increases the load of lumbar isthmus under flight overload. The results provide more accurate data support for the formulation of training programs and the development of protective devices to ensure flight safety