Neuropathic pain (NP) is a chronic disease caused by damage to the peripheral or central nervous system. Connexin 43 (Cx43), the primary connexin expressed by astrocytes, has been reported to be significantly increased in NP. However, the roles and mechanisms of Cx43 in the development and maintenance of NP remain largely unknown, while microglia activation has been commonly regarded as a key factor of NP. In the present study, we found that Cx43 deletion significantly ameliorated spared nerve injury (SNI)-induced NP and suppressed SNI induced c-Fos expression in the spinal cord. Notably, Cx43 deletion led to much less SNI-induced microglia activation in the spinal cord. These results suggest that astrocyte Cx43 may play a significant role in regulating microglial activation and NP.