InP quantum dots (QDs) have emerged as promising nanomaterials in various fields due to their exceptional optical properties. However, its wide emission linewidth limits further application. In this study, we synthesized high-quality InP/ZnSe/ZnS QDs by suppressing hole defects. The unreacted In precursors during nucleation easily enter ZnSe in the subsequent shelling process, forming a hole trapping center that adversely affects the photo-excitons radiative recombination. Our results demonstrate that the presence of In ions in ZnSe shell enhances exciton-phonon coupling, broadens the fluorescence emission spectrum, and weakens exciton binding energy. The optimized InP QDs exhibit a line width of 44 nm and 90% PLQY at 630 nm. Furthermore, our investigation into the interaction between shell hole defects and core exciton function provides valuable insights for designing and preparing another high-performance core-shell heterojunction QDs.