The stereocomplex crystal (SC) in poly(l-lactide)/poly(d-lactide) (PLLA/PDLA) blends provide great opportunities to enhance the performance of PLA materials. Unfortunately, obtaining the SC in high-molecular-weight (PLLA/PDLA) blends is still a challenge. In this study, halloysite nanotubes (HNTs) are used to induce the crystallization of SC in PLA with a high molecular weight. By investigating the non-isothermal and isothermal crystallization behaviors of PLLA/PDLA/HNTs, it is demonstrated that HNTs promote SC growth over homocrystal (HC). According to the investigations of crystallization morphologies and molecular interactions, it is deduced that weak interactions between HNTs and PLA induced the accumulation of PLLA and PDLA, and the high lattice matching promoted the growth of SC. This would encourage the usage of SC crystals in PLA samples in the industry.