A method of an optical sensor device used for detecting a color of a specific surface of an object includes: providing a sensor array having a plurality of pixel units each for receiving light reflected from the specific surface to generate a sensed pixel value; using the sensor array to generate a specific image formed by a plurality of sensed pixel values; determining whether the specific image is similar to a first solid color image corresponding to a first color according to the plurality of sensed pixel values of the specific image; and determining to execute a distance detection operation to calculate a specific distance from the optical sensor device to the specific surface according to a color saturation value of the first color in the specific image when it is determined that the specific image is similar to the first solid color image corresponding to the first color.