Introduction: The use of standard rodent model, allows for the understanding of neuronal injury physiopathology and helping development of therapeutic strategies. Because of eliminating technical problems, we designed a modified impactor device with ability to induce different degrees according to kilodyne from very mild to very severe of spinal cord injury (SCI) and traumatic brain injury (TBI) models in rat. Methods: For standardization and determining of optimal performance of the device to induce varying injuries, 47 adult male Wistar rats were used, and 8 different forces were applied in spinal cord and brain tissues. Results: The hematoxylin and eosin and 2, 3, 5-triphenyltetrazolium chloride (TTC) results demonstrated that by increasing the level of forces, histological changes in the spinal cord and brain were significantly enhanced. Different injuries had significant effect on the Basso-Beattie-Brenham and elevated body swing test outcomes, and there were significant differences between groups in comparison with control group. Conclusion: Our results showed that the modified device could be valid to produce precise SCI and TBI models, goal to replicate SCI and TBI in humans as much as possible. However, it might be considered that aspects of SCI and TBI models are complicate and more examination is necessary.