Dual-wavelength LEDs with doped quantum well barriers of different doping concentrations are numerically investigated by using the APSYS simulation software. The carrier concentrations, radiative recombination rates, energy band diagrams and spectra are investigated at different doping types and different doping concentrations. The results show that through adjusting the doping concentration of the quantum well barrier a suitable spectrum can be obtained, which will satisfy the need of application. And the effect of spectrum-control in dual-wavelength LED is due to the blocking effect of electrons and holes by doped quantum well barriers.