Traumatic brain injury (TBI) is a recognized global public health problem. However, there are still limitations in the available therapeutic approaches and a lack of clinically effective drugs. Therefore, an in-depth exploration of the secondary pathological mechanism of TBI and the identification of new effective drugs are urgently needed. Cannabidiol (CBD), a component derived from the cannabis plant, has potential therapeutic effects on neurological diseases and has received increasing attention. However, few reports on CBD intervention in TBI patients exist. Here, we use the Feeney free-fall method to establish a rat TBI model. CBD significantly improves neurological deficit scores, neuronal damage and blood-brain barrier permeability in rats and significantly inhibits the expressions of the brain injury markers S-100 beta and NSE. Mechanistically, CBD attenuates TBI-induced astrocyte activation, reduces inflammation, and attenuates the expressions of inflammatory prostaglandin system indicators. The use of TG6-10-1 (EP2 inhibitor) and H-89 (PKA inhibitor) indicates that CBD attenuates TBI-induced neurological damage via the PGE2-EP2-cAMP-PKA signaling pathway. Overall, this research provides a novel drug candidate for the treatment of clinical brain trauma.