Organic light-emitting diodes (OLEDs), as a new generation display and lighting technology, are critical for charge transport and luminescence efficiency enhancement. The study determines the potential, electron and hole concentrations in OLED devices based on Poisson’s equation and current continuity equation, and fits the charge transport process in the devices with the drift-diffusion model. The differential equations are solved by improved Euler’s method and iterative solution method to simulate the operating state of the OLED device. In conjunction with experiments, the enhancement effects of the OLED devices optimized based on the differential equation model in terms of charge transport and luminescence efficiency are analyzed. The optimized device and the comparison device exhibit the same partial pressure and a largely overlapping luminescence curve at 450~460 nm, but the optimized device lifetime and brightness are better than the comparison device. The charge transfer efficiency of the optimized device exceeded 99.99%, while that of the comparison device was lower than 95%. In addition, the light extraction efficiency of the optimized device is more than 20% higher than that of the comparison device, and it has the highest current efficiency, i.e., the optimized device has a better luminescence efficiency. The differential equation model is used in OLED devices to describe the processes of charge transport, optical properties, etc. The model can be used to systematically optimize the material properties and improve the overall efficiency of OLED devices.