A method for detecting a location of a subject vehicle capable of an autonomous driving by using a landmark detection. And the method includes steps of: (a) a computing device, if a live feature map is acquired, detecting each of feature map coordinates on the live feature map per each of reference objects included in a subject data region corresponding to a location and a posture of the subject vehicle, by referring to (i) reference feature maps corresponding to the reference objects, and (ii) the live feature map; (b) the computing device detecting image coordinates of the reference objects on a live image by referring to the feature map coordinates; and (c) the computing device detecting an optimized subject coordinate of the subject vehicle by referring to 3-dimensional coordinates of the reference objects in a real world.