The image method is one of the common methods for detecting LOS stabilization accuracy of an airborne electro-optical pod, which is simple in theory and versatile with low cost.A carrier simulator is used to impose external disturbances on the electro-optical pod, and detect the offset of the fixed target image captured by a load camera, so as to obtain the stabilization accuracy of the electro-optical pod.Above all, the detection of target image offset is the key to the whole process.This paper proposes a method for detecting the target image offset based on the image′s grayscale, which can effectively improve the detection accuracy of the optical axis′s boresight stability.Through theoretical derivation and experiments, it is proved that the detection accuracy of target image offset is above 1/100 pixel,which has high value in engineering application.