Objective To evaluate left ventricular function and ventricular wall motion disorder by two-dimensional speckle tracking echocardiography (2D-STE) in children with influenza A-related myocarditis. Methods Thirty children with influenza A-related myocarditis were selected as the case group, and 33 children who came in for routine check-ups were used as the normal control group. Routine ultrasonography was performed on both groups, and two-dimensional speckle tracking technology was used to evaluate cardiac function and global longitudinal strain of the left ventricle. Comparative analysis was conducted between the two groups. Results There was no significant difference in age, body surface area, end-diastolic left ventricular diameter (LVIDd), diastolic interventricular septal thickness (IVSd), early diastolic and late diastolic mitral flow velocity ratio (E/A) and CK-MB between the case group and the normal control group (P>0.05). Compared with the normal control group, the heart rate and hsTnI level were higher, and the left ventricular ejection fraction (LVEF), ratio of early diastolic mitral annulus velocity (E/E') and left ventricular global systolic strain peak (GLPS) were lower in the case group, and the differences were statistically significant (P<0.05). GLPS was positively correlated with LVEF and negatively correlated with IVSd, but not significantly correlated with LVIDd, E/A, E/E’, hsTnI, CK-MB and electrocardiographic parameters. The optimal cutoff value of GLPS for the diagnosis of influenza A-related myocarditis in children was -19.9 %. Conclusions Left ventricular long-axis strain of 2D-STE can accurately reflect the changes of left ventricular myocardial mechanical properties in children with myocarditis caused by influenza A virus infection. It can be used as a simple, safe, reliable and practical new means for early diagnosis, follow-up and prognosis evaluation of influenza A-related myocarditis.