<p>Polypropylene, a versatile thermoplastic resin, has emerged as one of the most rapidly expanding and innovative types among the five general-purpose synthetic resins, attributable to its excellent mechanical qualities, non-toxicity, simplicity of processing and molding, and comparatively low cost. Nucleating agent modification has emerged as the most prevalent and successful strategy for enhancing the performance and transparency of polypropylene, owing to its little technical complexity, operational flexibility, and simplicity. In recent years, research on the modification of nucleating agents (NAs) has deepened significantly, encompassing a diverse array of NAs, and interest in related studies continues to escalate. This work examines <i>α</i> crystalline NAs, such as sorbitol derivative, substituted aromatic heterocyclic phosphate salts, and organic carboxylate salts, as well as <i>β</i> crystalline NAs, including aliphatic dicarboxylic acid salts and aromatic diamide NAs. This work outlines various compounding procedures for <i>α</i> and <i>β</i> crystalline NAs and comprehensively examines the nucleation mechanisms of these agents. The recent advancements in polypropylene modification are encapsulated through an examination of nucleating agent classifications, research applications, and nucleation mechanisms, with a projection of future trends in NAs for polypropylene modification.</p>