In order to study the mechanical properties of GFRP plate-concrete composite beams, the ABAQUS finite element software was used to establish the concrete beam model reinforced by glass fiber reinforced composites (GFRP). The load-span deflection curve and bearing capacity of composite beams were verified to show the rationality of establishing a model method. The component models of three different strength grades of C25, C30 and C40 were designed, and the conclusions about the mechanical properties of GFRP plate-concrete composite beams were analyzed. Conclusions:(1)The results show that under the same load, the ultimate bearing capacity of the composite beam increases with the increase of concrete strength grade, and the ductility decreases with the increase of concrete strength grade.(2) Increasing the concrete strength grade can effectively increase the ultimate bearing capacity of the composite beam.(3) GFRP panels can improve the flexural capacity of composite beams.(4) GFRP plateconcrete composite beam is mainly divided into two stages:elastic stage and working with crack.