An optical navigation device and a method thereof, wherein the optical navigation device comprises a pair of linear sensor arrays which are arranged non-parallel to each other for detecting light signal. Furthermore, an algorithm including correlation and vector analysis is processed by a computation unit to determine velocity and displacement according to present and previous light signal data sequences. Hence, the linear sensor arrays adapted to be the approach of navigation device can achieve the goal of reducing the computing data, increasing operation speed effectively and reducing hardware cost because of its fewer optically sensitive elements.