Based on SAAS mode andtrust related research overview, this paper focused on the trust evaluationsystem of SAAS model Information Service System of the establishment, aroundthe hard environment (system characteristics, software quality, condition,etc.) and soft environment (system protection, market reaction) to provideprotection for the user, of Information Service System, trust issues from theperspective of enterprise-class applications, to determine the evaluationindex, build trust evaluation system of evaluation system of InformationService System in SAAS mode, and select the analytic hierarchy process andfuzzy comprehensive evaluation on SAAS enterprise representative empiricalcomparative study.