Abstract: Provided are thermoplastic organic fibers including a copolymerized resin of maleic anhydride with polypropylene, a method for preparing the same, a fiber composite board using the thermoplastic organic fibers as a matrix, and a method for manufacturing the fiber composite board. The thermoplastic organic fibers solve the problem of a limitation in improvement of strength caused by low wettability and adhesion between the thermoplastic organic materials used as a matrix according to the related art and reinforcing fibers.