Abstract: Quantum dots (QDs) nanocrystals possess outstanding narrow linewidth and easy tuning of size and emission wavelength, making them a rising star in the field of nanomaterials. The application of quantum dot light emitting diodes (QLEDs) has also garnered attention from researchers. In this study, through the design of material ratios, the size and emission wavelength of CdZnS-QDs are tuned to enhance the performance of auxiliary devices in CdSe-QDs-based QLEDs. Ultimately, blue-purple CdZnS-QDs with photoluminescence wavelengths ranging from 425 to 455 nm are obtained. The use of wide bandgap CdZnS-QDs as an inorganic interlayer material in the device optimizes band alignment, exciton transfer, and interface modification for CdSe-QDs as the emitting layer in QLEDs. Through comparative experiments to explore the optimal QDs synthesis strategy and precise control of the QDs' emission peaks, well-crystalline and uniformly sized quantum dots were prepared. These CdSe-QD-based electroluminescent devices incorporated CdZnS-QDs as an intermediate layer between the emitting layer and the inorganic electron transport layer. The resulting devices demonstrated a significant improvement in brightness, increasing from 227188 cd/m² to 313775 cd/m² at a current density of 1000 mA/cm², with a maximum current efficiency of 38.1 Cd/A. This method opens up new avenues for the design of QLED structures.