Abstract: Phosphate glass (P-glass)/polypropylene (PP) composites were prepared. The effects of P-glass with different glass transition temperature (T_g) on the crystalline and mechanical properties of PP matrix were studied. The experimental results show that the crystallization temperature of the PP matrix was markedly increased by adding P-glass, in which P-glass with low-T_g plays a crucial role in the heterogeneous nucleation process of PP. The addition of low-T_g P-glass leads to the formation of β crystals and obvious improvement in toughness. The elongation at break of the composites increases from 427% to 545%, and the impact strength increases from 18.6 kJ/m² to 36.8 kJ/m².