Abstract: In order to study the temperature-dependent photoelectric characteristics of the extended wavelength In0.8Ga0.2As PIN infrared detectors, based on planer process with sealed-ampoule diffusion method, front-illuminated 2561 linear planar InGaAs detector arrays were fabricated on NIN-InAs0.6P0.4/In0.8Ga0.2As/InAs0.6P0.4 buf./InP materials by metal organic chemical vapor deposition (MOCVD). And the I-V characteristics, spectral response and detectivity of the detector at different temperatures were analyzed. The results indicate that the forward dark current is dominated by the generation-recombination current and gradually becomes the diffusion current with temperature dropping. Diffusion current and generation-recombination current were the main resource of reverse current of the detector between 260 K and 300 K. The tunneling current predominated at temperature below 180 K. The cutoff wavelength and peak wavelength were 2.57 m and 2.09 m at room temperature. The peak detectivity, peak responsivity and quantum efficiency was 7.25108 cmHz1/2/W, 0.95 A/W and 56.9% respectively. Furthermore, the average peak detectivity of the detector arrays reached a peak value of 1.111011 cmHz1/2/W and the response nonuniformity was about 5.28% at 153 K.