Objective:To matrix metalloproteinase-9 (MMP- 9) combined with myocardial calcium proteinⅠ (CTnI) detection of viral encephalitis combined myocarditis early diagnosis significance. Methods:Atotal of 90 patients with diagnosis of children with viral encephalitis, according to whether merger myocarditis situation divided into two groups, including viral encephalitis group of fifty cases, combined with myocarditis group and an example, and select twenty cases of healthy check-up children as control group. All respondents were measured serum levels of MMP-9 and CTnI levels. Results:The viral encephalitis combined myocarditis and viral encephalitis group and control group with MMP-9 first measurement were 423.18+/-99.26, 293.23+/-75.9, 118.89 66.87 mm;Three groups of CTnI determination for the first time was 2.73+/-1.25, 0.76+/-0.53. Compared with the control, viral encephalitis group and viral encephalitis combined with myocarditis MMP-9, CTnI levels increased significantly, p<0.05, and the merger myocarditis serum MMP-9, CTnI levels also significantly higher than that of viral encephalitis group (p<0.05). Conclusion:Serum MMP-9 joint CTnI detection in the early diagnosis of viral myocarditis is of important significance.