The green light emitting diode (LED) with an insertion layer between the multiple quantum wells and n-GaN layer was grown on c-plane sapphire substrate by metal organic chemical vapor deposition.We investigated the structural and optical properties of the LEDs with and without insertion layer.It was found the insertion layer could promote the combination of In concentration,and induced an overall red-shift of wavelength.We speculate that the In phase separation and piezoelectric field would be responsible for the wavelength red-shift,the performance of LED deteriorated either.