Provided are a method and system for processing a low-illuminance image. The system includes an image acquisition unit to acquire two images having different levels of illuminance and sensitivity as first and second images; a motion vector estimation unit to extract a motion vector of the second image based on the first image; an image correction unit to correct the second image using the extracted motion vector; a synthesis coefficient calculation unit to calculate a synthesis coefficient used to synthesize the first image and the corrected second image; and an image synthesis unit to synthesize the first image and the corrected second image using the calculated synthesis coefficient.