A method for detecting motion information includes the following steps. First, a pixel array is provided for detecting an image of a measured object located in a first distance range or in a second distance range, and the pixel array includes a plurality of invisible image sensing pixels and a plurality of visible image sensing pixels. Then, image detection is conducted within the first distance range by using the invisible image sensing pixels to output a plurality of invisible images. Next, the image detection is conducted within the second distance range by using the visible image sensing pixels to output a plurality of visible images. Then, the plurality of invisible images and the plurality of visible images are analyzed by using a processing unit, so as to obtain motion information of the measured object. A pixel array for detecting motion information and an image sensor are also provided.