Aiming at the problem of Key Performance Parameter (KPP) requirement sequence in campaign requirement of weapons and equipment, put forward a point of using sensitive degree analysis method to rank KPP scientifically and reasonably. KPP requirement sequence model of weapons and equipment is introduced, analyses the steps and builds system efficiency model on the example of a kind of Chinese auto-mobile cannon. The result indicates that the method can reckon how much degree the KPP affects system efficiency intuitionisticly and scientifically. Sensitive degree analysis which many factors vary simultaneously will be researched at next step.