Air-to-ground firepower coordination is an important form of air-to-ground cooperation in air defense operations. Scientific and efficient design of coordination strategies， such as coordination styles， coordination rules， and process control， can effectively improve the effectiveness of air-to-ground firepower coordination. This paper， based on the coordination degree and coordination complexity of firepower coordination between air-to-ground cooperative weapon platforms， proposed three firepower coordination styles： tactical level， tracking level， and guidance level， and presented typical cooperative action modes under each type. Based on this， three basic coordination rules， including firepower use by domain， flexible firepower control， and firepower safety evasion， as well as specific criteria， were proposed. The coordination control process and detailed steps between the coordinating entities and coordinated objects were designed， and an evaluation index system for air-to-ground firepower coordination was constructed. The research results have high application value for the design of air-to-ground cooperation architectures and the construction of firepower coordination models.