This study investigates the biomechanical effects of different seat inclinations on the cervical spine of fighter jet pilots under high-load conditions. It assesses the stress, strain, and injury risk to the cervical spine during two flight scenarios: rapid pull-up and stable circling maneuvers. Based on the 50th percentile pilot anthropometric data from Chinese military standards, a detailed finite element model of the cervical spine, including vertebrae, intervertebral discs, and ligaments, was constructed. The model’s validity was confirmed by comparing the experimental data of vertebral range of motion and axial impact. By applying acceleration profiles corresponding to rapid pull-up and stable circling maneuver conditions, the biomechanical responses of pilots were simulated at seat inclinations of 17° and 22°. The study analyzes the effects of different seat angles on cervical spine stress, strain, and displacement. It employs the Neck Injury Criterion (NIC) to assess the risk of spinal cord injury in the neck. Under both conditions, a seat inclination of 22° significantly increased the stress and displacement in the vertebrae and intervertebral discs, though it did not reach the threshold for direct injury. The C5-C6 intervertebral disc experienced the highest stress during rapid pull-ups, indicating that the lower cervical spine bears greater loads under high-load conditions. The C3–C4 and C4–C5 intervertebral discs showed a notable increase in stress during stable circling maneuvers, reflecting differences in loading patterns under varying flight conditions. The NIC values for both seat angles did not reach the threshold for spinal cord injury; however, higher seat inclinations resulted in elevated NIC values, suggesting potential risks associated with prolonged exposure to high-load environments. Greater seat back inclinations increase the biomechanical load on pilots’ cervical spines, elevating the risk of neck-related ailments. This study provides scientific evidence for the design of fighter jet seats and pilot protection strategies. It is recommended that seat inclination effects on the cervical spine be comprehensively considered in the design process to ensure pilots’ long-term health and safety.