A method to detect the movement of an image sensor according to captured images. An image region is captured from a first image. Then, a first corresponding region matching the first region is captured from a second image. A second image region is captured from the second image. Then, a second corresponding region matching the second captured image region is captured from the first image. Finally, the movement of the image sensor is determined according to the first region and the first corresponding region when a first relative distance between the first region and the first corresponding region is the same as a second relative distance of the second captured image region and the second corresponding region, but in the opposite direction.