Miniature air launched decoys （MALD） can trick ground air defense radar into turning on and consume air defense ammunition， significantly reducing the effectiveness of air defense operations and improving aircraft formation penetration capability. After summarizing the development of MALDs， this paper analyzes the target characteristics of MALD and constructs typical operational scenarios. The influence of MALD on the detection and tracking performance and the interception efficiency of guidance radar is analyzed. The influence of long-range deception and closed jamming on guidance radar by MALD are studied through theoretical analysis and dynamic simulation. The influences of several factors on aircraft formation penetration efficiency are investigated based on queuing theory. The research conclusion can provide a theoretical reference for MALD operation.