It is widely held that compared with a legislature with a single majority party, a multi-party legislature achieves more precise representation of society. But the scope of such an advantage that a multi-party system has is rarely discussed. We study the range of social preferences that a three-party system can realize through majority voting. We present a procedure to construct a three-party system that will induce the policy choice specified by a given social preference relation. We provide a sufficient condition for a social preference relation to be compatible with some three-party system. The condition describes a certain restriction on the structure of cycles of social preference relations.