A self-localization device and a method thereof are provided. The self-localization device has a movable carrier, a first laser image-taking device and a processor. The movable carrier can be moved and rotated on a plan. During the motion of the movable carrier, the first laser image-taking device disposed on the movable carrier acquires an i-th lot point data in the space at a time point ti, where i is one index number from 1 to n, and n is an integer. The processor controls the first laser image-taking device, and receives coordinates of the i-th lot point data. The processor executes a K-D tree algorithm to perform a comparison and merge process between the first and the i-th lots point data, so as to establish a two dimensional profile.