The light weight compound sandwich board is a kind of light weight energy saving compound board. material taking fiber reinforced calcium silicon board or cement calcium silicon board as panel, with cement, EPS, fly ash as fillers and forming by one time compund.The product can replace construction materials as red brick, clay solid brick,air brick,color-coated steel sandwich board,gypsum block,wire spatial grid structure perlite board,perlite porous board etc. It can wikdely be applied to wall materrials of various high and low buildings such as bank, office building, hospital, school, hotel,mall,amusement hall, active barrack,old house reconstruction, residence and workshop.