In　the　setting　of　traditional　secure　two-party　computation,　one　party　may　either　tell　a　wrong　output　to　the　other　party　or　abort　the　protocol　after　he　obtains　the　computation　output.　So,　completed　fairness　can　not　be　achieved.　To　address　this　problem,　combining　game　theory　with　cryptography,　a　rational　secure　two-party　computation　protocol　is　proposed　in　this　paper.　Firstly,　we　suppose　that　any　rational　party　would　prefer　getting　the　computation　output　to　not　getting　it　and　secondly,　it　is　preferred　that　as　few　as　possible　of　the　other　players　get　it.　Then,　game　strategies,　utilities,　and　motivations　that　participants　deviate　from　the　protocol　or　abide　by　the　protocol　are　researched,　and　a　game　model　for　secure　two-party　computation　is　constructed.　In　the　protocol,　it　is　a　best　strategy　for　parties　to　abide　by　the　protocol.　The　cheating　of　party　can　be　detected　and　the　gain　of　the　following　the　protocol　is　more　than　the　gain　of　deviating,　so　rational　party　has　incentive　to　abiding　by　the　protocol.　Finally,　every　party　can　obtain　the　computation　result.　Analysis　shows　that　the　protocol　is　secure　and　fair.