Objective To detect the expression of macrophage inlfammatory protein 1α(MIP-1α) in the myocardium of viral myocarditis (VMC) mice at different phases. Methods A total of 120 4-week-old male BALB/c mice were randomly divided into 2 groups, 80 in the VMC group and 40 in the control group. Mice in VMC group were inoculated intraperitoneally with coxsackievirus B3 to build VMC models, while mice in control group were treated with DMEM cultivate liquid. Ten mice of each group were sacriifced on days 3, 7, 15 and 30 after treatment and their heart tissues were collected for analysis. The level of MIP-1αin the myocardium was determined by immunohistochemistry. Myocardial histopathology was examined with hematoxylin and eosin stain. In addition, the relationship between the level of MIP-1αand the degree of myocardial lesion was investigated. Results The expression of myocardial MIP-1αprotein in VMC group was up-regulated in myocardium on day 3 after inoculation of virus, and slowly decreased after the peak on day 7, but still sustained a high level on day 30. Compared with the control group, the levels of MIP-1αin VMC group were increased signiifcantly at every phase (P<0.05). Furthermore, positive correlation was found between MIP-1αprotein expression levels and myocardial histopathologic scores in VMC group (r=0.94, P<0.01). Conclusion The up-regulated expression of MIP-1αmay play a critical role in the pathogenic mechanisms of viral myocarditis.