The utility model provides a battery ystem installation fixes triangle arm support, its characterized in that includes floorbar, supporting beam and curb girder, the floorbar cross -section is the L type just by long curb plate and short bottom plate integrated into one piece, it is the L type just by long curb plate and short bottom plate integrated into one piece to prop up the supporting beam cross -section, the long curb plate of floorbar with the short bottom plate that props up supporting beam is fixed mutually, the short bottom plate of floorbar with the long curb plate that props up supporting beam is fixed mutually, the both ends of curb girder be fixed in respectively on long curb plate and a supporting beam's of floorbar the long curb plate to make curb girder, supporting beam and the floorbar to constitute firm right triangle structure. Simple process, weight ratio tradition support is light, with low costs, and the intensity of support obviously obtains improving, and the practicality is high.