Objective  To investigate the effect of MCC950 on inflammatory pain induced by formaldehyde in mice.    Methods  Seventy-two male ICR mice were randomly divided into six groups, including saline control group (NS), formaldehyde model group(F), different doses of MCC950 intervention group (6.25 mg/kg MCC950+F, 12.5 mg/kg MCC950+F, 25 mg/kg MCC950+F, 50 mg/kg MCC950+F). The spontaneous pain was determined by the cumulative time of licking paw in mice. The expressions of immediate early genes (IEGs), such as c-Fos, Arc, early growth response protein 1(Egr-1), in the spinal cord were determined by Real-time PCR. The expression of c-Fos in the spinal cord was determined by immunohistochemistry.    Results  Spontaneous pain score showed that compared with the NS group，F group showed typical biphasic pain, however 12.5 mg/kg, 25 mg/kg and 50 mg/kg MCC950 intervention decrease significantly the second phase pain compared with the F group. The result of Real-time PCR showed that the mRNA level of c-Fos, Arc and Egr-1 in the spinal cord of  F group enhanced remarkably compared with the NS group, while it could be reversed by 50 mg/kg MCC950 treatment. The result  of immunohistochemistry showed that the number of c-Fos positive cells in the posterior horn of spinal cord of the F group increased significantly compared with the NS group, while it could be reversed by the treatment with 50 mg/kg MCC950.    Conclusion  MCC950 can alleviate the inflammatory pain induced by formaldehyde in mice, which may be related to the down-regulation of IEGs in the spinal cord.