The invention provides a method for conducting non-uniformity correction on sub-pixel images through multi-linear-array time difference scanning. The method includes the steps that (1) a multi-linear-array time difference scanning detection device is constructed; (2) each linear array detector conducts scanning imaging in the scanning direction according to a sampling interval, Nt groups of image data are obtained through each time of imaging, and the step (3) is conducted immediately; (3) the Nt groups of image data of each linear array detector are processed to form a frame detection image; (4) the frame detection images are spliced to obtain the two sub-pixel images; (5) cross splicing is conducted on the two sub-pixel images according to columns to form an image Ip1; (6) an image Ip2 processed through column-wise non-uniformity correction is obtained; (7) two sub-pixel images processed through column-wise non-uniformity correction are rebuilt; (8) the two sub-pixel images are rotated by 90 degrees in the same direction to obtain an image Ip3; (9) two sub-pixel images processed through line-direction non-uniformity correction are rebuilt; (10) the two sub-pixel images are rotated by 90 degrees in the reverse directions.