The nervous system is a vital component of the human body, and its dysfunction can have fatal consequences or severe adverse effects. After significant disabling conditions, the nervous system is not able to recover damaged parts. Schwann cells are needed in a short period to regenerate nerve cells, but they do not support axonal growth-permissive phenotype. In this regard, implanting growth factors, small molecules, stem cells, and biological macromolecules in peripheral nerve injury would promote axonal outgrowth. In this review, the nervous system, related injuries, and essential factors applied for nerve regeneration are systematically highlighted.