1. A method for recognizing and locating an object, the method comprising: performing an offline mode process comprising steps of: (a) analyzing a template image of the object, so that plural sampled edge points of the template image and respective gradient angles and a gravity position of the plural sampled edge points are obtained; and (b) obtaining plural similarity score tables according to the plural sampled edge points, a predetermined detecting distance range and a predetermined gradient angle difference range; performing an online mode process comprising steps of: (c) analyzing a live image, so that plural edge points of the live image and respective gradient angles of the plural edge points are obtained; and (d) calculating plural predictive gravity positions corresponding to the plural edge points of the live image, and calculating or summing up plural similarity scores corresponding to the plural predictive gravity positions according to plural similarity scores of the plural similarity score tables, wherein the predictive gravity position with the similarity scores higher than a threshold value is correlated with the gravity position of the template image, thereby recognizing and locating the object.