The reflection spectra of Al_0.5Ga_0.5As-AlAs distributed Bragg reflector (DBR) at different incident angle are calculated by transfer matrix method. The reflection spectra curve of p-polarized and s-polarized plane waves vary with a ‘V’ shape with the rise of the incident angle and the lowest reflectivity is at 49.8°. The reflection spectra of different incident media [air and Al0.7Ga0.3)0.5In0.5P] are greatly different at different incident angles. The change of the reflection spectrum from air to DBR is small, the reflectivity is 88.13% at incident angle 0° as well as 84.98% at 45°, and the peak wavelength of reflection spectrum is blue-shifted about 10 nm. But the change of reflection spectrum of from (Al0.7Ga0.3)0.5In0.5P to DBR is great, the reflectivity decreases over 45% and the peak wavelength is blue-shifted over 127 nm from incident angle 0°to 45°.In order to reduce the changes, a new multi-wavelength DBR design is brought forward. The theoretical result shows the reflectance spectrum of multi-wavelength DBR design is better than that of the conventional DBR design, which is important to enhance light extraction from LED.