In　this　paper,　a　new　equivalent　circuit　model　of　GaN-based　light　emitting　diodes　(LEDs)　is　established.　The　impact　of　the　series　resistance　to　luminous　efficacy　is　simulated　using　the　MATLAB　software.　GaN-based　LEDs　with　different　n-contact　electrode　materials　(LEDs　with　Ni/Au　and　LEDs　with　Cr/Au)　are　fabricated.　By　comparing　and　analyzing　the　results　of　performances,　we　concluded　that　both　the　series　resistance　and　the　carrier　loss　could　affect　the　luminous　efficacy　severely.　LEDs　with　lower　series　resistance　have　higher　luminous　efficacy　and　its　efficiency　droop　is　alleviated　simultaneously.　To　improve　luminous　efficacy,　the　fabrication　process　should　be　optimized　for　lower　series　resistance.