This paper investigates the spontaneous and piezoelectric polarization effects of InGaN/GaN Multiple Quantum Well（MQW）LED with a sapphire substrate.In order to analyze its output characteristics

it imitates InGaN/GaN MQW blue LED chips in the traditional horizontal structure by using MATLAB software.The study shows that the same proportional increase on various interfacial polarization charges of LED can weekly improve its electrical characteristics

but significantly reduces its light output power and internal quantum efficiency chiefly because interfacial charges change the energy band structure

hinders the diffusion and drift of the holes and reduces the radiative recombination coefficient.Changing the dislocation density can reduce the impact of the polarization charge on the LED and improve its performances.