Using blue chip to stimulate YAG phosp hor is the main method to achieve white LED.But in the method,the red emission c omposition is missing,which leads to the device with low color rendering index.I n this paper,organic red material MEH-PPV with the mass fraction of 5%,10%,15%, 20% are mixed by adding YAG phosphor.The experiments show that the abosrbance of organic red material MEH-PPV in the region of yellow and green light gradually increases.And a stronger red emission near 615nm is observed.The red compositi on is supplied compared with the traditional blue LED chip to stimulate YAG phos pher,and the emission band extends to 700nm.When the organic red material MEH- PPV mixed with mass fraction of 15%,the highest color rendering index of the pre pared white LED can achieve 92.With the continued increase in mass fraction from 15% to 20%,the color rendering index of the device begins to decrease.This is b ecause the energy emitted by the LED chip can stimulate the organic red material of MEH-PPV,and MEH-PPV has strong absorption in green region from the pho sphors,so the best color ratio exists to achieve the best performance of the dev ice.