A　new　approach　has　been　proposed　in　this　work,　which　provides　an　effective　way　for　tuning　the　structural　transition　in　MM＇X　systems　with　relatively　high　transition　temperature.　With　this　method,　a　temperature　window　as　wide　as　275　K　for　the　magnetostructural　transition　has　been　achieved　in　the　MnNiSi　alloy　system.　The　maximum　magnetic　entropy　change　of　the　system　is　as　high　as　13.3　J/kgK,　which,　together　with　the　large　temperature　window,　enables　the　Mn0.4Fe0.6NiSi1-xGax　system　to　be　a　promising　candidate　for　magnetic　refrigerant　applications.　(C)　2016　Author(s).　All　article　content,　except　where　otherwise　noted,　is　licensed　under　a　Creative　Commons　Attribution　3.0　Unported　License.