Disclosed are coding and decoding methods using patterns and a system thereof. The object-images are obtained via detecting a pattern comprising objects. The distances between the object-images are obtained and a code is found based on the obtained distances between the object images. The distances between the object-images are defined as distances between centers of the object-images. As there are at least three objects in a pattern, a code is obtained based on a ratio of distances between object-images, which equals to a ratio of distances between objects. As there are at least four objects in a pattern, it is first determined whether a first ratio of object-images equals to a predetermined ratio of object-images. If no, a second ratio of object-images is obtained via a correcting factor and the first ratio of object-image, and finally a code is obtained based on the second ratio of object-images.