Viral myocarditis refers to localized or diffusive myocardial inflammation induced by virus infection. In western medicine, treatment is based on nurturing cardiac muscle cells and relieving cardiac burden, but the effects are not satisfying. Traditional Chinese medicine has achieved remarkable effects in treating this disease. Collateral Theory, an important constituent of TCM, takes collateral-vascular diseases as major research field and mainly focuses on regularity of outbreak and development, basic pathologic changes, clinical manifestations and drug implementation of vascular diseases. Discussions on pathological mechanisms of viral myocarditis based on collateral theory have shown great significance in improving clinical effects. According to pathogenic factors and pathologic changes of viral myocarditis, collateral obstruction due to qi and yin deficiency was regarded as basic pathogenesis, thus the method, supplementing qi and nourishing yin to resolve stasis and dredge collaterals, should be viewed as the major principle, put forward based on the theory of “vacuity being treated by supplementing and repletion being treated by draining”. Collateral theory clarifies syndrome differentiation and essential commonly-used traditional Chinese medicinal, providing effective thoughts and methods for the treatment of viral myocarditis.