Objective:To explore the effect of phosphorylation of neuronal nitric oxide synthase (nNOS) on regulation the neuropathic pain in spinal nerve ligation (SNL) model rats,and research the mechanism of nNOS phosphorylation in neuropathic pain. Methods:A total of 60 male SPF SD rats were randomly divided into 4 groups:the control group,only expose spinal nerve,not ligation;the experimental group,SNL model,KN93 (calcium/calmodulin dependent kinase Ⅱ inhibitor) intrathecal injection;the negative control group,SNL model,DMSO intrathecal injection;the model group,SNL model,didn′t receive any medicine. We determined mechanical pain threshold 1 day before operation,postoperative 1-5 days and 1-4 hours after sheath dosing. Western blot was performed to detect the expression level of calcium/calmodulin dependent kinase Ⅱ (p-CaMKⅡ),nNOS and pnNOS in lumbar spinal cord tissue. CoIP and immunofluorescence experiments was performed to test whether there was an interaction between nNOS and CAPON. Results:SNL led to mechanical pain threshold of rats reduced (P < 0.01),the expression of spinal cord tissue p-CaMKⅡincreased (P < 0.05),and the expression of p-nNOS decreased(P < 0.05). KN93 intrathecal injection reversed the trend above. There was an interaction between nNOS and CAPON,and the phosphorylation of nNOS reduced the strength of interaction between nNOS and CAPON. Conclusion:The phosphorylation of nNOS is involved in neuropathic pain induced by SNL,and p-CaMKⅡ make nNOS phosphorylation,reduced the strength of interaction between nNOS and CAPON. The nNOS signaling pathways can provide a new field of vision for neuropathy pain treatment.