Due to a number of contradictory design requirements of missile launch systems with outstanding performances， such as heavy load， light weight， low cost and rapid response， parameter-matching optimization on multiple constraints is indispensable. In respect to above problems， association rule mining is applied to study the effect of launch system design factors in this paper. Association rules mining model of launch system design factors is established. In addition to support-confidence framework， Kulc and IR are led into pattern evaluation to enhance the mining accuracy. An engineering example is carried out to study the effect of design parameters on rapid response. The results of the example indicate the method in this paper is able to identify the factors that play critical roles in rapid response and to realize the purpose of design space refining， optimization problems simplification and design optimization efficiency improvement.