This paper aims to investigate the semantic function of Ruguoshuoconditionals in Mandarin Chinese. The purpose of this study is to explain the differences of Ruguo and Ruguoshuo conditionals(or hypothetical). According to the factuality of the contents of the antecedents, Ruguoshuo conditionals can be defined as factual conditionals with negative epistemic stance of Speaker. From the perspective of factual conditionals, Ruguoshuo-conditionals emphasizes on metaphor reasoning, rather Ruguo sentences emphasized on the logical reasoning which indicates material implication(if p, then q). It is suggested that this characteristics can be analyzed with a theory of three conceptual domains as put forward in Sweetser(1990). The Ruguoshuo sentences belong to either epistemic or speech-act conditionals(not content conditionals). In speech-act domain, Ruguoshuo sentences have meta-linguistic functions, and used for speech-act of refutation, request, etc.