The efficiency of a light-emitting diode (LED) is limited because a large amount of generated light is confined inside due to total internal reflection. It is well known that light extraction from LEDs can be enhanced by using photonic crystal. However, the underlying physical mechanisms for increased emission are still largely unknown. In this work, we used the finite difference time domain method to analyze the photonic crystal (PC) LED with disordered air holes. The light extraction efficiency of disordered PC was nearly equivalent to that of ordered PC with the same pattern periodicity. This result supported the idea that the increased light extraction of PC LED was mainly due to the scattering, which is irrelevant to photonic band structure.