Air attack formation is a tactical group formed by the airplanes in different combat missions, the distribution of it is an important basis for the air defense commander to analyze the purpose of the enemy air attack and make the campaign decision. The air attack formation possesses the following characteristics: large in airplane quantity, great in distribution range and needs a rapid analysis of enemy's situation. According to the air target's data characteristic, a method and steps for classifying the air target group based on dynamic clustering technique are established. This algorithm has a better astringency and can meet rapid analysis demand for command and control system. Based on this, an algorithm for calculating the campaign parameters inside the target group and among the groups are put forward and an analysis model of the enemies' primary air attack direction and attack purpose is presented according to the attack formation quantity distribution and fairway shortcut. Finally, a material example is put forward, and the result is identical with the commander's judgment on the whole. In engineering practical application the air target can be fast clustered by using this model, which can provide a quantitative foundation to the region air defense commander in control of the air situation accurately and making decision quickly.