Terahertz waves have been attracting more attention because of their growing applications in brain science. Most of the studies have demonstrated that terahertz waves have a certain positive impact on neurons. They can promote the growth of ganglion processes and the release of neurotransmitters, but the specific mechanism is still largely unexplored. Our study found that terahertz waves could promote neuronal excitability. Moreover, numerous differentially expressed proteins were uncovered via proteomic analysis. Among them, CaMKIIδ is a subunit of CaMKII and could promote the release of neuronal transmitters, regulate the excitability of neurons, and enhance synaptic plasticity. We further demonstrated that CaMKIIδ actively increased synaptic plasticity through the NF-κB pathway. This study provided a potential target for nerve repair and disease treatment.