Unsaturated polyester/benzoxazine copolymer was employed to prepare polyester/benzoxazine/glass fiber compositelaminates and their mechanical, morphological, and thermal properties were investigated. Compared with those of 100UPR/0PBZ/10GFcomposites, the tensile strength and flexural strength of 90UPR/10PBZ/10GF composites with 10 wt % polybenzoxazine content wereincreased by 10 % and 6 %, respectively. The enhancements in mechanical properties are mainly due to the strong interfacial adhesionsbetween glass fiber and UPR/PBZ matrices, which were confirm by the SEM images of fracture surfaces of the composites. Curingbehavior of glass fiber filed composite was investigated by differential scanning calorimetry analysis. All UPR/PBZ/GF compositelaminates are thermally stable up to 270 0C in air. Furthermore, TGA thermograms revealed that the degradation temperatures ofUPR/PBZ/GF composite increased with compare UPR/GF composite. UPR/PBZ/GF composite laminates will have potentialapplications in the areas where require of excellent mechanical properties and high temperature resistance.