Aiming at the lacking of accuracy and criterion of current weapon equipment system description, proposed the method of noumenon -based weapon equipment system formalization description, on the basis of researching on the weapon equipment system capability, capability index system, relations of capabilities, capability hierarchy structure etc. And taking the beyond-the-horizon air combat capability of air battle weapon equip system as example to carry out formalization description. The example shows that the method can improves the accuracy of weapon equipment system capability description. Furthermore, it can provide basic data for the capability analysis for the future.