Abstract: Simulation model reuse is a hot research issue in modeling and simulation(M&S) domain.The main difficulty of model reuse lies in evaluating the reusability of a certain simulation model in a new application.The relevant concepts of simulation model reuse,such as reusability,context,model assumptions,model constraints,experimental frame,scope frame and reusable simulation model,are formally and consistently given first.Then the evaluation theory and algorithms of reusability are present.Two parts of the algorithms,context interfaces compatibility evaluation and behavior logics equivalence judgment,are detailed respectively.The use strategy of this contribution and completed work are also discussed.