Aiming at the problem of air target's intention estimation, an air target tactical intention estimation model is established. In the existing airborne situation awareness system, the function of air target tactical intention estimation is added to evaluate the tactical intention of enemy air targets in the airborne environment in real time and assist pilots to make air combat decisions.Around the model of air target tactical intention estimation, the multi-granularity fuzzy Bayesian network is used to estimate the target intention. The simulation results show that the improved membership function is more accurate to evaluate the intention of the target, which improves the reference in the actual decision-making process and verifies the effectiveness of the model.