In this paper, we study the relations between the number-noise squeezing of the output light of a LED driven by high-impedance constant-current source and LED's electronic/optical quantum efficiencies, ieakage current effect, negative feedback of photon-flux fluctuation and noise frequency. We poiat out that with appropriate negative-feedback of the photon-flux fluctuation, LED driven by high-impedance constant-current can generate number-squeezed state light, the number-noise squeezing is significantly enhanced and its ideal value is limited only by residual noise of the high impedance constant-current source, LED's leakage current effect and quantum efficiency.