Organic light emitting diode (OLED) devices possess the characteristics of light weight,low power consumption,high response speed and flexibility.They have shown the great superiority in the flat panel display and solid-state lighting.In order to enhance the performance of OLED devices,the Expert OLED software was used to simulate the actual OLED devices with different grating structures.The electroluminescent (EL) spectrum,the luminous angle and the electric field distribution were analyzed in the OLED devices with bimetal electrodes.The optimized micro/nano grating structures was obtained.And for OLEDs with different grating periods,the varied grating height has different effects on the luminescence performance.We can also improve the luminescence performance by adjusting the molecular dipole orientation of emitting layer and optimizing the electric field distribution in the OLEDs.This work provides a valuable reference on improving the performance of OLEDs by using the optimized periodic micro/nano grating structures.