An optical navigating apparatus, which comprises: a light source, for illuminating a surface to generate an image; an image sensor, for catching pictures of the image; and a controller, for computing a first estimating speed of the optical navigating apparatus according to a first picture of the pictures and a second picture after the first picture. The controller controls at least one of parameters as following according to the first estimating speed: a non-illuminating frequency that the light source does not illuminate pictures after the second picture; a non-catching frequency that the image sensor does not catch pictures after the second picture; a computing frequency that the controller computes pictures after the second picture, which are caught by the image sensor; and a searching range for pictures after the second picture.