The invention relates to the new usage of puerarin in the field of pharmaceutical products, in other words, it relates to the application of puerarin in the preparation of drugs for P2X3 mediated pain/nervous system diseases. The experiment shows that puerarin can inhibit pain-related behavioral responses, subsequently immunohistochemical analysis, in situ hybridization, RT-PCR, protein blotting and other techniques were utilized to observe the inhibition of puerarin on mRNA and protein expression of P2X3 receptor in dorsal root ganglion of rats with neuropathic pain and in dorsal root ganglion and sensory nerve ending in the burn model of rats, it was found by using whole-cell patch clamp technique that puerarin can significantly reduce the electric current activated by P2X3 receptor agonist in the neuron of dorsal root ganglion of rats with neuropathic pain. The experiment proves that the mechanism for the inhibitory effects of puerarin on acute and chronic pain is to block the transmission of pain sense information that is mediated by P2X3 receptor in primary sensory neurons. The invention provides a kind of new method for the prevention and treatment on acute and chronic pain, and it also indicates that puerarin can act as a antagonist for P2X3 receptor, which will be helpful for the application of drugs in the prevention and treatment on P2X3 receptor involved nervous system diseases.