The　structure　and　magnetic　properties　of　ferromagnetic　Tb1-xGdxFe2　system　have　been　studied　through　the　morphotropic　phase　boundary　(MPB),　a　phase　boundary　between　two　ferroic　phases　of　different　crystal　symmetry.　Morphotropic　phase　boundary　(MPB)　has　been　studied　extensively　for　its　extraordinary　enhancement　effect　in　ferroelectrics.　Based　on　same　mechanism,　we　have　designed　a　pseudobinary　ferromagnetic　system　Tb1-xGdxFe2,　of　which　the　near-MPB　composition　Tb1-xGdxFe2　shows　maximum　magnetization　under　small　field,　and　meanwhile　dramatically　the　low　magnetostriction.　With　synchrotron　x-ray　diffractometry,　the　crystal　structure　of　TbFe2-rich　compositions　is　detected　to　be　rhombohedral　and　that　of　GdFe2-rich　compositions　is　tetragonal　below　their　curie　temperatures.　The　near　MPB　composition　Tb(0.1)Gd(0.9F)e(2),　shows　the　maximum　magnetization　among　all　available　compositions　and　superposition　of　magnetostriction　behavior　of　R　and　T　phases.　To　find　MPB　phenomena　in　ferromagnets　may　provide　a　new　route　to　design　functional　materials　in　other　ferroic　MPB　systems.