In this work, hydrophobic nano-silica (SiO2) and β-nucleating agent are incorporated into polypropylene random copolymer (PP-R) matrix by melt blending. The effect of the content of nano-SiO2/β-nucleating agent on the crystallization and mechanical behaviors of PP-R was investigated in detail. For a nano-SiO2 content of 0.5 wt% and a β-nucleating agent content of 0.5 wt%, the tensile strength and impact strength of the composite were in a more balanced position. Regarding isothermal and non-isothermal crystallization experiments, nano-SiO2/β-nucleating agent significantly accelerated the nucleation and growth of crystallites with a synergistic nucleation effect. Also, the crystallization kinetics of PP-R/nano-SiO2/β-nucleating agent, PP-R/nano-SiO2 and PP-R/β-nucleating agent composites were analyzed and compared using the Avrami equation. The results showed that the PP-R/nano-SiO2/β-nucleating agent composites have better crystallization rate and shorter semi-crystallization time. This study shows far-reaching theoretical and practical implications for accelerating the development of new high-performance PP-R materials.