Based on spatial filtering velocimetry, a new method is proposed by using spatial filtering effect of line CCD for aerial camera. Spatial filtering characteristic of spatial slits is simulated by doing interval sampling with line CCD image, by which an optical non-contact measurement about aerial camera image motion velocity is realized. Besides, with the research of spatial filtering power spectrum density function, key factors affecting the spatial filtering characteristic of line CCD are analyzed. The possibility of measurement about image motion velocity with line CCD push broom image simulating spatial filtering effect is validated with experiments. The results show that the measurement error is less than 1/3 pixel for an image motion velocity between 5 and 53.2 mm/s, which satisfies the requirement of image motion compensating precision for aerial camera.