With the development of network centric warfare, the situation awareness and information processing ability of tactical edge are becoming more and more important due to the rapidly changing war situation. Tactical cloud based on the technology of cloud computing can provide tactical edge with powerful computing storage and information processing ability. The technical characteristics of four type of tactical cloud architecture are analyzed and a tactical cloud scheme based on software definition is proposed, which provide various application for the mobile device at the tactical edge and at the same time can guarantee the QoS of the applications and optimization of wireless resource utilization.