The　difficulty　of　quantum　key　agreement　is　to　realize　its　security　and　fairness　at　the　same　time.　This　paper　presents　a　new　three-party　quantum　key　agreement　protocol　based　on　continuous　variable　single-mode　squeezed　state.　The　three　parties　participating　in　the　agreement　are　peer　entities,　making　same　contributions　to　the　final　key.　Any　one　or　two　participants　of　the　agreement　cannot　determine　the　shared　key　separately.　The　security　analysis　shows　that　the　proposed　protocol　can　resist　both　external　and　internal　attacks.