Abstract: In recent years, bendable flexible electronic devices have attracted widespread attention, but the performance stability and bending stability of the devices have hindered their practical applications. In this paper, we focus on the changes of functional film and device performance before and after bending of flexible quantum dot light-emitting diodes (QLEDs) by applying bending force to QLEDs. The film parameters and device electrical properties were tested by regulating the bending radius of QLEDs. The polyethylene terephthalate-indium tin oxide (PET-ITO) composite transparent electrodes with different bending radii were analyzed by the finite element method, and the results show that as the bending radius decreases, the ITO electrode shows a more obvious stress concentration phenomenon. The morphological characterization and square resistance tests show that excessive bending will cause damage to the electrode material and increase the square resistance. Transient electroluminescence spectroscopy (TREL) was used to characterize the devices before and after bending. The results show that the decrease in the bending radius of curvature reduces the efficiency of charge transfer on the electrode, and the smaller bending radius of curvature leads to the increase of internal defects, which reduces the efficiency of carrier injection and transfer inside the device and affects the performance of the device.