Abstract: In air surveillance radar operations, complex electromagnetic interference is ubiquitous and directly impacts the quality of air situation acquisition as well as the selection of countermeasure strategies by operators. To enable operators to intuitively grasp the overall interference severity, we analyze the adverse effects of interference on target detection performance, including degraded detection capabilities, track quality, and interference intensity, based on the radar's inherent anti-jamming capabilities. A hierarchical interference level assessment index system is proposed using the multi-level Analytic Hierarchy Process (AHP), and an interference level assessment model is established. This model provides critical guidance for operators in selecting effective countermeasure strategies.