The invention discloses an Archimedes spiral push-scan filtering differential gas leakage infrared imaging method which is suitable for an infrared focal plane detector. The method comprises the following specific steps: (1). designing an Archimedes spiral filter disk including a background optical filter, a leakage gas optical filter and two light barrier sheets, wherein the optical filters and the light barrier sheets are arranged in an alternative manner; (2). obtaining a leakage gas image, a background image and light barrier images A and B by using the filter disk to perform push-scan on the detector; (3). performing difference operation between the leakage gas image and the A and the B respectively, obtaining an average difference result and then obtaining a leakage gas image without blind elements; and performing difference operation between the background image and the A and the B respectively, obtaining an average difference result and then obtaining a background image without blind elements; (4). using the A and the B for calculating a non-uniformity correction model and performing non-uniformity correction on the results obtained in step three; and (5). carrying out difference operation between the corrected leakage gas image and the corrected background image and obtaining a final image. The method provided by the invention is suitable for differential infrared imaging of a leakage gas.