There is provided a dual mode optical navigation device. The dual mode optical navigation device is configured to operate in a first mode or a second mode on a working surface. The dual mode optical navigation device includes an image sensor and a processor. The image sensor captures an image frame of the working surface. The processor calculates a ratio of a bright area and a dark area in one image frame capture by the image sensor, enters the first mode in response to the calculated ratio being larger than a ratio threshold, and enters the second mode in response to the calculated ratio being within a ratio threshold range. The ratio threshold range is smaller than the ratio threshold.