To improve the judging and decision-making ability on air target threats in air defense operations, an air target threat assessment method is proposed based on Relevance Vector Machine (RVM) and Artificial Bee Colony (ABC) algorithm. From the reality of air defense operations, the air target threat index system is firstly constructed according to mathematical statistical analysis, and then ABC algorithm is used to optimize the parameters involved in the multi-kernel RVM to establish an air target threat assessment model. Simulation analysis shows that, the proposed method is a high-precision air target threat assessment method, and it is better than RVM method with single Gauss kernel or single Sigmoid kernel in all accuracy indices, thus confirming its effectiveness and feasibility.