Abstract: The prepolymer method was used to prepare the glass fiber reinforced self-crosslinking polyurethane (GF/PU) composites, in which three functional polyether polyol (PPG) and two phenyl methane diisocyanate (MDI) acted as the soft and hard segments, respectively. The effects of the polymerization temperature of PU prepolymer, pot-life of application, crystallinity and content of GF on the dynamic mechanical and mechanical properties of the GF/PU composites were studied by using rotating viscometer, DMA, SEM, XRD and mechanical testing machine. The results show that the GF/PU composites exhibit the highest performance comprehensive performance when the polymerization temperature of the PU prepolymer is 50℃ and the mass fraction of GF is 55wt%. The tensile strength, flexural strength, and impact toughness of GF/PU composite are 794 MPa, 846 MPa and 228 kJ/m², respectively. The peak value of dynamic mechanical properties loss factor (tanδ) is 0.59.