The tensile fracture strength of polymer matrix composites at different temperatures has always been an important concern. As a common reinforcement phase, particles can significantly improve the tensile fracture strength of polymer matrix composites. However, with the increase of particle volume fraction, particles tend to agglomerate, which affects the strengthening effect. For particle-reinforced polymer composites, with considering the effects of particle agglomeration, as well as the evolution of the thermo-physical performance with temperature, a temperature-dependent analytical model for predicting the tensile fracture strength of particle-reinforced polymer composites was developed. The model predictions were in good agreement with the experimental data. The research results provide an effective way to quantitatively characterize the tensile fracture strength of composites with different particle contents and temperatures, and deepen the understanding of the influence of agglomeration phenomenon on the mechanical properties of composites at different temperatures.