Military Reports（T’ang-pao, 塘報）were quite common to people in Ming times, so that they used this term without explanation in the historical materials left down to the present time. Modern historians, confused by the term, tried hard to explore the true meaning of it, even extorting or making up the origins for Miltary Reports, when failed to find out the right answer. This article, hence, first traces the development of the Military Reports system back to the military barriers along the seashore of the empire in early Ming times. Secondly, this article analyzes the structure and contains of Military Reports and concludes that, because of their comparatively low speed of transmission, Military Reports, instead of being information relied on by the court to control battles, could serve only as data basis on which the central government formed long-term stratgies and policies. Thirdly, this article points out that, as very important historical materials, Military Reports have to be prudently treated, culling histonical facts from those forged or exaggerated. The systems of Military Reports and Residential Reports（Ti-pao, 邸報）jointly formed the nerve network of the Ming empire and, consequently preserved precious documents for modern historians to reconstruct the political and institutional aspects of the Ming Dynasty.