Abstract: To research the time complexity of indirect interaction patterns quantitatively,fuzzy-timing Petri nets models of three basic indirect interaction patterns were proposed as well as fuzzy time complexity of three indirect interaction patterns.Reachability tree searching algorithm from sponsor to receiver of integrated interaction pattern could deal with the three indirect interaction patterns and calculate fuzzy time complexity of integrated interaction pattern.Finally,an instance was used to analyze the application of indirect interaction patterns in the prosses of establishing integrated interaction pattern.The method can evaluate time complexity of integrated interaction pattern and help choosing integrated interaction patterns.