The invention discloses an FRP grid concrete composition board and a manufacturing method thereof. The FRP grid concrete composition board comprises an FRP grid and concrete poured into grid holes or concrete which is poured into the grid holes and poured on a grid surface layer; the FRP grid comprises longitudinal and transverse middle bearing rods or comprises the longitudinal and transverse middle bearing rods and edge bearing rods arranged at the periphery of the board, and the grid holes are defined by the middle bearing rods or defined by the middle bearing rods and the edge bearing rods; the sections of the middle bearing rods and the sections of the edge bearing rods are each shaped like a wedge, that is to say, the upper portions are narrower than the lower portions. According to the manufacturing method of the composition board, except a conventional pouring method, some special technological methods can be adopted due to the flexible and diverse composition structure. The FRP grid concrete composition board is small in self weight, flexible in design, high in bearing capacity and good in corrosion resistance and has the advantages of being simple in structure, convenient to use and wide in application.