||Polylactide (PLA) is one of the most commonly used biodegradable polymers for various fields such as biomedical and renewable industries. Unfortunately, the mechanical and thermal properties of PLA are inevitably damaged during the molding process due to the slow crystallization rate. To overcome this limitation, a simple, novel, one-pot, self-accelerating method for the in situ self-nucleating (ISN-) polymerization of L-lactide is designed. This strategy results in the simultaneous polymerization and self-nucleation of L-lactide crystallites upon addition of a self-nucleating agent. The results show that ISN-PLA experiences an acceleration effect on the crystallization with sc-PLA as the nucleating agent. The ISN-polymerization of L-lactide can save considerable time and cost by using the one-pot process composed of both polymerization and self-nucleation. This study suggests a novel strategy for manufacturing industrial products with high strength and crystallinity based on PLA.