The current expansion of GaN-based LED is very important to the characteristics of devices. Two kinds of devices were introduced and their merits and drawbacks were compared and the current expansion was introduced. It is pointed out that the ring-N-electrode was propitious to the current expansion and proved by experiments. The characteristic of the ring-N-eledtrode was comparied with the common N-electrode,and there was 6% reduction at forward voltage(20 mA). The total radiation power of the device was also improved at the same forward current. When the device worked for 50 hours,the total radiation power of the ring-electrode device was enhanced 8% compared to the traditional device. The contribution of the ring-N-electrode was proved particularly.